Max SNR as Indicator of RX Performance?

[VE3MEO]

Is the Max SNR reported by DRM RX software and guessable from the DRMcalc graphing of DReaM software a good indicator of receiver performance? I'm guessing that, when propagation is good and noise and interference are low, the receiver with the higher Max SNR is the better receiver, at least in some respects. That is, it has lower phase noise, better phase-frequency linearity, lower IMD. These are the invisible characteristics while amplitude-frequency linearity is quite visible through the software's spectrum display.

I realise there are a lot of other factors that can affect SNR at any moment - fading, selective fading, man-made and atmospheric noise and interference, signal strength. Curiously, I have had the perception that received signal strength or IF SNR is not a significant determinant in the DRM SNR above a certain threshold. That some radios apparently give much higher DRM SNR than others suggests that these invisible factors are involved.

Perusing quite a few log reports, I have noticed some logs maxing out at 30 dB and others only 20 dB, even when successful audio decoding is at or near 100%. These are logs from different receivers in different locations. Would it be fair to expect that side-by-side on the same antenna that there will be a significant difference in decoding success?

What is the meaning of SNR in DRM? Is it calculated the same way in DRM RX and DReaM?

Tom

[VE3MEO]

Bernd reports a max SNR of 35.4dB in this message (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410). I have surveyed quite a few reports on drmrx.org and I think this is the highest I have seen.

Are there any others achieving over 30dB? Post your report of the highest SNR you have recorded in this thread with a description of your receiving system.

Thanks,
Tom

[Bob]

Hi,

These are results of my comparative test between a Winradio G303i and an RCA AR-88D vintage communications receiver.

The tests were both carried out on a DW-Radio transmission on 13790 KHz today. The first test was using the G303 fed by a Wellbrook LA5030 loop antenna feeding a Dell 8200 desktop v AR-88D/Sat Service Schneider LC mixer with longwire antenna feeding a Dell D600 laptop. For the second test I swapped the PC's and the antenna so hopefully the only variable is the receiver.

Quite interesting results (perhaps I should tell Winradio)!

regards
Bob
[Note : Incorrect DRMCalc txt files originally posted, now corrected see later message - after I deleted the attachment I couldn't reattach it to this message - apologies]

[VE3MEO]

Originally posted by Bob
Hi,

These are results of my comparative test between a Winradio G303i and an RCA AR-88D vintage communications receiver.

[snip]
Quite interesting results (perhaps I should tell Winradio)!

regards
Bob

I'll echo that. It's probably in part due to front end overload. Isn't the G303 a wideband receiver with no preselector? And the AR88 probably has the much higher overload immunity of a tube radio with preselector.

73, Tom

[Bob]

Originally posted by Bob
Hi,

These are results of my comparative test between a Winradio G303i and an RCA AR-88D vintage communications receiver.



Corrected attachment (only txt files changed).

regards
Bob

[VE3MEO]

Anyone interested in logging the highest SNR you have ever achieved with DRMRX/DReaM in a published table something like this?

<table>
<tr>
<B>
<td>Max SNR
<td>By
<td>Receiver
<td>Converter
<td>Antenna
<td>Service
<td>Freq(kHz)
<td>Date yyyy-mm-dd
</B>
</tr>
<tr>
<td>35.4 dB
<td>Bernd DF9RB
<td>TS850 AGC off
<td>
<td>
<td>DW Sines
<td>13790
<td>2004-09-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410)
</tr>

<tr>
<td>34.5 dB
<td>carknue
<td>AOR-7030
<td>?
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=9929#post9929)
</tr>

<tr>
<td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Svc Scheider LC
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)
</tr>

</table>

73, Tom

[VE3MEO]

Attached is an zip file with two screen shots of DReaM 1.1.1cvs - one with higher SNR and no audio decoded, the other with lower SNR and successful audio, both from the same test signal and system. It shows that the calculated DRM SNR is not an ideal indicator of receiver performance and optimal tuning. A receiver that results in a slightly higher reported SNR may not actually decode audio as successfully as the lesser one!

In the examples, the receiver is a Radio Shack DX-394A operating with no AGC into a NE612 downconverter with two 15kHz filters cascaded and the test transmitter is a NE612 upconverter with the DReaM transmitter. The only difference between the two is the tuning of the DX-394 - 10,252.4 kHz for lower SNR and 10,252.5 kHz for higher SNR but no audio.

This shift in frequency crosses a boundary that shifts the desired signal 5kHz at the 1st IF of 45MHz. The 5kHz shift at the 1st IF repositions the DRM signal in the passband of the relatively broad 45 MHz ceramic filter, resulting in the tilt of the spectrum changing between slightly downward and pronounced upward.

Apparently the algorithm for calculating SNR is more generous with the upward tilt or the consequential slight lifting of the central peak. But estimated channel impulse response shows a spreading or delay nearly double and audio is not decoded.

So higher SNR is not the be all and end all to highest success rate for audio decoding. Other factors must be considered. Apparently, impulse response is one of them - hence the interest in group delay distortion, to the extent that it affects impulse response.

73, Tom

[VE3MEO]

Highest SNR achieved with DRMRX/DReaM:

<table>
<tr>
<B>
<td>Max SNR
<td>By
<td>Receiver
<td>Converter
<td>Antenna
<td>Service
<td>Freq(kHz)
<td>Date yyyy-mm-dd
</B>
</tr>
<tr>
<td>35.4 dB
<td>Bernd DF9RB
<td>TS850 AGC off
<td>
<td>
<td>DW Sines
<td>13790
<td>2004-09-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410)
</tr>

<tr>
<td>34.5 dB
<td>carknue
<td>AOR-7030
<td>?
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=9929#post9929)
</tr>

<tr>
<td>31.4 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>NE612 protoboard
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-09-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=10974#post10974)
</tr>

<tr>
<td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Svc Scheider LC
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)
</tr>

</table>

73, Tom

[VE3MEO]

Highest SNR achieved with DRMRX/DReaM:

<table>

<tr>
<td>Max SNR
<td>By
<td>Receiver
<td>Converter
<td>Antenna
<td>Service
<td>Freq(kHz)
<td>Date yyyy-mm-dd
</tr>


<tr>
<td>35.6 dB
<td>arniek
<td>FRG-100
<td>Sat-Service Scheider
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
</tr>

<tr>
<td>35.4 dB
<td>Bernd DF9RB
<td>TS850 AGC off
<td>
<td>
<td>DW Sines
<td>13790
<td>2004-09-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410)
</tr>

<tr>
<td>34.5 dB
<td>carknue
<td>AOR-7030
<td>?
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=9929#post9929)
</tr>

<tr>
<td>33.4 dB
<td>dn0758
<td>elektor
<td>
<td>long wire
<td>DW Sines
<td>5980
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=11207#post11207)
</tr>

<tr>
<td>31.4 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>NE612 protoboard
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-09-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=10974#post10974)
</tr>

<tr>
<td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Svc Scheider LC
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)
</tr>

</table>

73, Tom

[arniek]

Hi all,

Even with the best RX performance you will never see high SNR values if you live in an area with much man-made noise.

My results in DRM-reception are best when i rotate the loop antenna for maximum SNR.

Using a longwire won't allow for such high SNR values in most cases as you're unable to rotate it ;-)

The better signal to noise ratio of loop antenna compensates for lower signal strength.

73

Arne

[VE3MEO]

Highest SNR achieved with DRMRX/DReaM:

<table align=LEFT border="1"><tr><td>Max SNR<td>By<td>Receiver<td>Converter<td>Antenna<td>Service<td>Freq(kHz)<td>Date
<tr><td>35.6 dB
<td>arniek
<td>FRG-100
<td>Sat-Schneider
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr>
<td>35.4 dB
<td>Bernd DF9RB
<td>TS850 AGC off
<td>
<td>
<td>DW Sines
<td>13790
<td>2004-09-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410)
<tr>
<td>34.5 dB
<td>carknue
<td>AOR-7030
<td>?
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=9929#post9929)
<tr>
<td>33.4 dB
<td>dn0758
<td>elektor
<td>
<td>long wire
<td>DW Sines
<td>5980
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=11207#post11207)
<tr>
<td>31.4 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>NE612 protoboard
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-09-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=10974#post10974)
<tr>
<td>30.2 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-09 (http://www.drmrx.org/forum/showthread.php?s=&postid=11218#post11218)
<tr>
<td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)
</table>


73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM:

<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>35.6 dB
<td>arniek
<td>FRG-100
<td>Sat-Schneider
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.4 dB
<td>Bernd DF9RB
<td>TS850 AGC off
<td>
<td>
<td>DW Sines
<td>13790
<td>2004-09-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410)
<tr><td>34.5 dB
<td>carknue
<td>AOR-7030
<td>?
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=9929#post9929)
<tr><td>33.4 dB
<td>dn0758
<td>elektor
<td>
<td>long wire
<td>DW Sines
<td>5980
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=11207#post11207)
<tr><td>31.7 dB
<td>hseppo
<td>AD8099, AD9834 DDS TUF-3 mxr
<td>?
<td>?
<td>DW Sines
<td>15440
<td>2004-10-10 (http://www.drmrx.org/forum/showthread.php?postid=11263#post11263)
<tr><td>31.4 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>NE612 protoboard
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-09-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=10974#post10974)
<tr><td>30.2 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-09 (http://www.drmrx.org/forum/showthread.php?s=&postid=11218#post11218)
<tr><td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)</td></tr>
</table>

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

73, Tom

<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>35.6 dB
<td>arniek
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.4 dB
<td>Bernd DF9RB
<td>TS850 AGC off
<td>
<td>DReaM 1.1.1c
<td>
<td>DW Sines
<td>13790
<td>2004-09-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=10410#post10410)
<tr><td>34.5 dB
<td>carknue
<td>AOR-7030
<td>?
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=9929#post9929)
<tr><td>33.4 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>long wire
<td>DW Sines
<td>5980
<td>2004-08-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=11207#post11207)
<tr><td>31.8 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>31.7 dB
<td>hseppo
<td>AD8099, AD9834 DDS TUF-3 mxr
<td>?
<td>DReaM 1.1.1c
<td>?
<td>DW Sines
<td>15440
<td>2004-10-10 (http://www.drmrx.org/forum/showthread.php?postid=11263#post11263)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>DRMSWR 2.0.34
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)</td></tr>
</table>

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

73, Tom

<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>37.4 dB
<td>Bernd DF9RB
<td>TS850 AGC inactive
<td>SA612 ceramic resonator
<td>DReaM 1.1.6c
<td>3-el ham Yagi
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12540)
<tr><td>36.5 dB
<td>CT1ADT
<td>TS-870 unmodified
<td>11,3 kHz out
<td>DRM 2.0.34
<td>8m vert or 24m dipole
<td>VOR
<td>15780
<td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
<tr><td>35.7 dB
<td>hseppo
<td>AD8099, AD9834 DDS TUF-3 mxr
<td>?
<td>DReaM 1.1.4c
<td>5m wire
<td>DW Sines
<td>17800
<td>2004-11-07 (http://www.drmrx.org/forum/attachment.php?s=&postid=12513)
<tr><td>35.7 dB
<td>simone
<td>FRG100 AGC off
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>loop
<td>DW Sines
<td>9685
<td>2004-11-23 (http://www.drmrx.org/forum/attachment.php?s=&postid=12511)
<tr><td>35.6 dB
<td>arniek
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.0 dB
<td>carknue
<td>AOR-7030
<td>Sat-Schneider xtal
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-01-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=5292)
<tr><td>34.9 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>Sony AN-1
<td>DW Sines
<td>17800
<td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
<tr><td>34.4 dB
<td>chemclouds
<td>Icom IC-R75 AGC off
<td>
<td>DRMSWR 2.0.34
<td>30m inverted-L
<td>CBC Sackville
<td>9800
<td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
<tr><td>34.3 dB
<td>FritzWue DK6QI
<td>FT840
<td>Sat-Schneider
<td>DReaM 1.1.6c
<td>2x 40m LW
<td>DW-Sines
<td>17800
<td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
<tr><td>33.4 dB
<td>df8uo
<td>FT757GX
<td>Sat-Schneider xtal
<td>DReaM 1.1.1c
<td>dipole
<td>VoR
<td>15780
<td>2004-11-06 (http://www.drmrx.org/forum/attachment.php?s=&postid=11951)
<tr><td>33.2 dB
<td>G3VRF
<td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
<td>12kHz DRM xtal ctld
<td>DReaM 1.1.6c
<td>35cm tuned loop in attic 11m a.g.
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
<tr><td>31.8 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.4 dB
<td>TimoHannes
<td>elektor
<td>?
<td>DRMSWR 2.0.34
<td>active
<td>DW Sines
<td>17800
<td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
<tr><td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>DRMSWR 2.0.34
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)</td></tr>
</table>

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/Dream

Congrats to TimoHannes, chemcloud, df8uo, CT1ADT, hseppo for making it onto or climbing up the list (http://www.drmrx.org/forum/showthread.php?s=&postid=11649#post11649) since it was last posted.

Rather than re-posting it each time, I've been editing the list, so the latest results will always have the same URL.

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

If you are on the list but some details are missing, please send me the needed info.

73, Tom

[schneider]

This "performance" called parameter i have propsed in our boock
"DRM- Empfangspraxis" publish house Fanzis- Verlag.

I have proposed a DRM- measuring input signal of more than -50 dBm (level not critical but strong signal) with S/N more than 40dB. The maximum of reached decoder S/N is called DRM- performance then.

To measure a amateur can use our DRM- measuring signal CD.
There You find a endless DRM measuring signal with more than 40 dB S/N. Play it by PC and modulate to RF by use of a NE612.

Attention! By measuring over an air signal no reproduction is possible ! The input S/N depends also at strong antenna signals from air noise, transmitter performance, multi path- conditions, unwanted signals and so on.

By use of the measuring signal the measurement is full to reproduce and characterises the receiver performance (linearity and phase noise of Lo`s).

U. Schneider
http://www.sat-schneider.de

[VE3MEO]

Originally posted by schneider
Attention! By measuring over an air signal no reproduction is possible ! The input S/N depends also at strong antenna signals from air noise, transmitter performance, multi path- conditions, unwanted signals and so on.


Yes, that's true. And there are other receiver characteristics that are not represented by the maximum attainable estimated DRM SNR - such as frequency stability which, if inadequate, will result in dropouts due to resynchronisation.

Over a prolonged period, the highest off-air SNR is likely to be very close to what the receiver is capable of under ideal test conditions. I think the table provides some indication of receiver performance. There are some models that have yet to make the list - for example, the ATS909, WinRadio, etc. Of course, I don't read every report posted and hope that thos who do succeed in breaking through 30dB will report it!

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/Dream

Congrats to John, G3VRF, for making it onto the list (http://www.drmrx.org/forum/showthread.php?s=&postid=11649#post11649) since it was last posted.

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

If you are on the list but some details are missing, please send me the needed info.

73, Tom

[hsseppo]

Hi Tom and all,

I have been testing my radios by use of SA612 mixer and Dream with -t option. My "home made" DDS receiver SNR was 43 dB and Sony ICF-2001D reached 28 dB SNR. When measuring over an air signal (Sines) I have got for Sony the maximum 28 dB SNR and DDS-receiver 35.7 dB SNR (Date: 2004-11-07 17800 kHz)


Both receivers decode audio almost identically, the difference is usually less than 1%. I think that the main problems with the DDS-receiver are the lo spurious and image rejection.

I have been planning to buy AD9951 DDS and use 55 MHz IF. Then image frequencies are easier to reject and because AD9951 has 14 Bit DAC, all DDS spurious are less than 80 dB. I am very satisfied the front end amplifier AD8099, as it has very low noise and high dynamic range. My receiver has about 100 dB dynamic range. There is no need to adjust gain during listening. The mixer is still a problem. Is the AD831 mixer better than TUF-3 ??

73's Seppo

Here is a short list of the Dream log:

DDS-receiver:
>>>>
Dream
Software Version 1.1.4cvs
Starttime (UTC) 2004-11-22 19:36:44
Frequency 8012 kHz
Latitude 60°12'N
Longitude 24°57'E
Label Dream Test
Bitrate 17.46 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0000 43 150 0/10 0
0001 43 150 0/10 0
0002 43 150 0/10 0
0003 43 150 0/10 0
0004 43 150 0/10 0

SNR min: 42.5, max: 43.1


Sony ICF 2001D:
>>>>
Dream
Software Version 1.1.4cvs
Starttime (UTC) 2004-11-22 19:36:45
Frequency 8012 kHz
Latitude 60°12'N
Longitude 24°57'E
Label Dream Test
Bitrate 17.46 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0000 28 150 0/10 0
0001 28 150 0/10 0
0002 28 150 0/10 0
0003 28 150 0/10 0
0004 28 150 0/10 0

SNR min: 27.5, max: 28.1

[VE3MEO]

Originally posted by hsseppo
I have been testing my radios by use of SA612 mixer and Dream with -t option. My "home made" DDS receiver SNR was 43 dB and Sony ICF-2001D reached 28 dB SNR. When measuring over an air signal (Sines) I have got for Sony the maximum 28 dB SNR and DDS-receiver 35.7 dB SNR (Date: 2004-11-07 17800 kHz)


List (http://www.drmrx.org/forum/showthread.php?s=&postid=11649#post11649) updated.

I, too, have tested with dream -t and a NE612 balanced modulator but have not achieved anything close to your results.

Both receivers decode audio almost identically, the difference is usually less than 1%. I think that the main problems with the DDS-receiver are the lo spurious and image rejection.


My view is that the threshold of tolerance for the average listener is an audio dropout rate greater than a few tenths of a percent. I would consider the difference between 99 and 99.9% successful audio to be huge to the listener but the difference between 50 and 51% to be negligible - most will have abandoned the station long before this point and gone to listen to AM or CD!

My receiver has about 100 dB dynamic range. There is no need to adjust gain during listening.


Awesome! So no AGC. And highest DRM SNR results from other receivers seem to be with AGC off.

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/Dream

Bernd, DF9RB, is the new leader on the list (http://www.drmrx.org/forum/showthread.php?s=&postid=11649#post11649) with 37.4 dB SNR from DW-Sines!

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

If you are on the list but some details are missing, please send me the needed info.

73, Tom

[cesco]

Originally posted by hsseppo
Hi Tom and all,

My "home made" DDS receiver SNR was 43 dB



Hi,
I am intrested in your "home made". Is there a documentation available ?

My own "homebrew" gets only max 27db snr on DW-werachtal,
about the same as the "normal" rx. It uses a 74hc4052 as quadrature mixer, no hf amp. Mirror image rejection is about 30db.

Cesco

[hsseppo]

Hi Cesco,

Here is the schematics of my DRM-radio. I use two DDS to feed the first and the second mixer. If I use ceramic 455 kHz filter, the mirror frequency is too close (910 kHz) the main freq., so I have made 12 MHz crystal ladder filter (6 crystals). I have also tested with 15kHz wide 21.4 MHz crystal filter. It is easy to change IF frequency as I have two DDS.

Here are links for the components:

AD8099 (http://www.analog.com/UploadedFiles/Data_Sheets/183075234AD8099_b.pdf)
Page 18, figure 66

AD9834 (http://www.analog.com/UploadedFiles/Data_Sheets/164749129AD9834_0.pdf)
Page 18 figure 16

MAX477 (http://pdfserv.maxim-ic.com/en/ds/MAX477.pdf)
TUF-3 mixer (http://www.minicircuits.com/cgi-bin/spec?cat=mixer&model=TUF-3&pix=b02.gif&bv=4)

Best Regards,
Seppo

[hsseppo]

Hi Cesco,

Here is the schematics of the DDS-unit.

Seppo

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/Dream

FritzWue DK6QI, has climbed onto the list (http://www.drmrx.org/forum/showthread.php?s=&postid=11649#post11649) with a 31.5 dB SNR from DW-Bonn on his FT840!

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

If you are on the list but some details are missing, please send me the needed info.

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/Dream

FritzWue DK6QI, has climbed up the list (http://www.drmrx.org/forum/showthread.php?s=&postid=11649#post11649) to 34.3 dB SNR from DW-Sines on his FT840!

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

If you are on the list but some details are missing, please send me the needed info.

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

Rene Schmitz squeezed out another 0.7 dB on Jan 11, one day after his last record high, now an amazing 38.9 dB with the following:
"The receiver is in constant flux, I now use an AD831 as the second mixer. The first mixer was the stock TUF-1. (I have socketed that.)
I would say it is a bit confusing to still call it Elektor RX, because there are more mods than original parts of the circuit. :-)

Antenna was the 5m Wire, and the preselector was also used."

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list. Is 40 dB within sight?

73, Tom

<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>38.9 dB
<td>René Schmitz
<td>Elektor custom IF, ADA831 2nd mxr, TUF-1,1st mxr preselector
<td>
<td>DReaM 1.1.6c
<td>5m wire
<td>DW Sines
<td>6130
<td>2005-01-11 (http://www.drmrx.org/forum/attachment.php?s=&postid=14300)
<tr><td>37.4 dB
<td>Bernd DF9RB
<td>TS850 AGC inactive
<td>SA612 ceramic resonator
<td>DReaM 1.1.6c
<td>3-el ham Yagi
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12540)
<tr><td>36.5 dB
<td>CT1ADT
<td>TS-870 unmodified
<td>11,3 kHz out
<td>DRM 2.0.34
<td>8m vert or 24m dipole
<td>VOR
<td>15780
<td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
<tr><td>35.7 dB
<td>hseppo
<td>AD8099, AD9834 DDS TUF-3 mxr
<td>?
<td>DReaM 1.1.4c
<td>5m wire
<td>DW Sines
<td>17800
<td>2004-11-07 (http://www.drmrx.org/forum/attachment.php?s=&postid=12513)
<tr><td>35.7 dB
<td>simone
<td>FRG100 AGC off
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>loop
<td>DW Sines
<td>9685
<td>2004-11-23 (http://www.drmrx.org/forum/attachment.php?s=&postid=12511)
<tr><td>35.6 dB
<td>arniek
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.0 dB
<td>carknue
<td>AOR-7030
<td>Sat-Schneider xtal
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-01-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=5292)
<tr><td>34.9 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>Sony AN-1
<td>DW Sines
<td>17800
<td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
<tr><td>34.4 dB
<td>chemclouds
<td>Icom IC-R75 AGC off
<td>
<td>DRMSWR 2.0.34
<td>30m inverted-L
<td>CBC Sackville
<td>9800
<td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
<tr><td>34.3 dB
<td>FritzWue DK6QI
<td>FT840
<td>Sat-Schneider
<td>DReaM 1.1.6c
<td>2x 40m LW
<td>DW-Sines
<td>17800
<td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
<tr><td>33.4 dB
<td>df8uo
<td>FT757GX
<td>Sat-Schneider xtal
<td>DReaM 1.1.1c
<td>dipole
<td>VoR
<td>15780
<td>2004-11-06 (http://www.drmrx.org/forum/attachment.php?s=&postid=11951)
<tr><td>33.2 dB
<td>G3VRF
<td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
<td>12kHz DRM xtal ctld
<td>DReaM 1.1.6c
<td>35cm tuned loop in attic 11m a.g.
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
<tr><td>31.8 dB
<td>VE3MEO
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.4 dB
<td>TimoHannes
<td>elektor
<td>?
<td>DRMSWR 2.0.34
<td>active
<td>DW Sines
<td>17800
<td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
<tr><td>30.0 dB
<td>Bob
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>DRMSWR 2.0.34
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)</td></tr>
</table>

73, Tom

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/Dream

The highest SNR received off air is now 38.2 dB! See the list (http://www.drmrx.org/forum/showthread.php?s=&postid=13974#post13974) for details! Is 40 dB possible?

If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list.

If you are on the list but some details are missing, please send me the needed info.

73, Tom

[VE3MEO]

Now Rene makes 38.9 dB dB! See the list (http://www.drmrx.org/forum/showthread.php?s=&postid=13974#post13974) for details!

Can you smell 40 getting close? A top flight transmitter and the right propagation and interference conditions and he should make it. Go Rene!

73, Tom

[Rene Schmitz]

Hi Tom and all,

I would guess that most people on the list could do 40dB. Its the propagation lottery. :-)

As for the topic of whether Max SNR is indicating RX performance, I'd say that its one aspect, that shows IMD and phase noise performance. But it says little about weak signal performance, dynamic range, and things like mirror frequency rejection. (Consider the low first IF that I'm using...)
But together with these more traditional characteristics, it should give an estimate.

Cheers,
René

[df9rb]

Hello Rene,

I have the 40 db vision since I started dreaming. To reach this goal I modified the AGC of my TS850 (but still the best SNR with AGC OFF), modified the mixer, tried several filters (between 30 kHz and 6 kHz), used attenuators different soundcards and antennas - but without success until now. So my congratulation for your best result so close to the 40 dB.
I would like to add to all of the factors you mentioned one additonal:
- the SNR at the transmitters antenna

Did anyone receive DRM close to a transmitter and what was the SNR there?


73 de Bernd, DF9RB

[Rene Schmitz]

Hi Bernd and all,

Thanks!

It would be very interesting to get results from the nearfield of a TX. I am a couple km away from the AM TX of WDR here in Bonn, 774kHz, maybe some day they'll start using DRM. :-)

It would be interesting to know what the reference receivers at the various sites acheive in SNR. Anyone?

Cheers,
René

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

This is a listing in descending SNR of reported Max DRM SNR as logged by DRMRX and Dream software, and analysed by Carknue's DRMcalc. It's for fun but might yield some useful tips for better reception. If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list. 40 dB off-air SNR has been surpassed!

73, Tom
<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>42.1 dB
<td>René Schmitz, Bonn, Germany
<td>Elektor custom IF, ADA831 2nd mxr, TUF-1,1st mxr preselector
<td>
<td>DReaM 1.1.6c
<td>5m wire
<td>DW Sines
<td>11830
<td>2005-02-05 (http://www.drmrx.org/forum/showthread.php?s=&postid=14947#post14947)
<tr><td>41.2 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>TS850 AGC inactive
<td>SA612 ceramic resonator
<td>DReaM 1.1.7c
<td>3-el ham Yagi, ALA1530, 30m wire
<td>Voice of Russia
<td>15780
<td>2005-01-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=14778#post14778)
<tr><td>37.9 dB
<td>simone, Bad Salzschlirf, Germany
<td>FRG100 AGC off
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>11830
<td>2005-02-08 (http://www.drmrx.org/forum/attachment.php?s=&postid=15035)
<tr><td>36.7 dB
<td>df8uo, Karlsruhe, Germany
<td>FT757GX
<td>Sat-Schneider xtal
<td>Dream 1.1.1c
<td>dipole
<td>DW
<td>11830
<td>2005-03-20 (http://www.drmrx.org/forum/showthread.php?s=&postid=15781#post15781)
<tr><td>36.5 dB
<td>CT1ADT, Sines, Portugal
<td>TS-870 unmodified
<td>11,3 kHz out
<td>DRM 2.0.34
<td>8m vert or 24m dipole
<td>VOR
<td>15780
<td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
<tr><td>35.7 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9834 DDS TUF-3 mxr
<td>?
<td>DReaM 1.1.4c
<td>5m wire
<td>DW Sines
<td>17800
<td>2004-11-07 (http://www.drmrx.org/forum/attachment.php?s=&postid=12513)
<tr><td>35.6 dB
<td>arniek, Muenster, Germany
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.4 dB
<td>Han, Netherlands
<td>AOR AR 7030 unmodified
<td>Sat-Schneider
<td>DReaM 1.1.7c
<td>?
<td>DW Sines
<td>11830
<td>2005-02-09 (http://www.drmrx.org/forum/showthread.php?s=&postid=15370#post15370)
<tr><td>35.0 dB
<td>carknue, Frankfurt, Germany
<td>AOR-7030
<td>Sat-Schneider xtal
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>VoR
<td>15780
<td>2004-01-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=5292)
<tr><td>34.9 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>Sony AN-1
<td>DW Sines
<td>17800
<td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
<tr><td>34.4 dB
<td>chemclouds, Richmond, Va, USA
<td>Icom IC-R75 AGC off
<td>
<td>DRMSWR 2.0.34
<td>30m inverted-L
<td>CBC Sackville
<td>9800
<td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
<tr><td>34.3 dB
<td>FritzWue DK6QI 52N 07E
<td>FT840
<td>Sat-Schneider
<td>DReaM 1.1.6c
<td>2x 40m LW
<td>DW-Sines
<td>17800
<td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
<tr><td>34.3 dB
<td>Kjell Holen LA6XJ Bergen, Norway
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.1.7c
<td>70 cm indoor loop
<td>Voice of Russia
<td>12060
<td>2005-01-15 e-mail
<tr><td>34.2 dB
<td>Werner DK8FT
<td>IC R71 AGC off
<td>Sat-Schneider xtal
<td>Dream 1.1.6
<td>4m wire
<td>DW-Sines
<td>17710
<td>2005-02-20 not posted
<tr><td>33.2 dB
<td>G3VRF, Warwickshire , UK
<td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
<td>12kHz DRM xtal ctld
<td>DReaM 1.1.6c
<td>35cm tuned loop in attic 11m a.g.
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
<tr><td>31.8 dB
<td>Tom VE3MEO Toronto, Canada
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.4 dB
<td>TimoHannes, Petäjävesi, Finland
<td>elektor
<td>?
<td>DRMSWR 2.0.34
<td>active
<td>DW Sines
<td>17800
<td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
<tr><td>30.0 dB
<td>Bob, St Albans UK
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>DRMSWR 2.0.34
<td>long wire
<td>DW Sines
<td>13790
<td>2004-09-10 (http://www.drmrx.org/forum/showthread.php?s=&postid=10495#post10495)</td></tr>
</table>

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=14421#post14421)

73, Tom

Jan 16: Bernd, DF9RB scores a 39.2 dB max SNR from VoR on 15780 and moves into 1st place!

Jan 15: Kjell Holen, LA6XJ, makes his first appearance on the list with 34.3 dB on a Sat-Schneider DRT1 from VoR on 12060. That's the 1st appearance of that receiver on the list, too; it's supposed to be capable of >40 dB SNR, according to the manufacturer, so look for Kjell to climb.

Jan 14:
Daniel, DF8UO, climbed a few spots to #7 today with a 1.7dB improvement in his personal best. He writes:
I am following the race to 40 dB in the forum. My configuration is nothing special, just a slight modification of my amateur equipment FT757GX and the non XTAL version of the SAT Schneider modul. I did not change any filters, just soldered a small coax before the 455 kHz IF and connected to the module.

However i noticed that the soundcard is very important. Since i use an external Creative Soundblaster Audigy, results are much better compared to the internal AC97 onboard sound.

[VE3MEO]

Once thought to be unattainable in over-the-air reception, in the last couple of days, not one, but two DRM pioneers broke the 40 dB DRM SNR barrier! And not by a hair but a wide margin.

First it was Rene Schmitz and DW-Sines on Jan 30 and then, one day later, Bernd, DF9RB, pulling in Voice of Russia. With but 0.1 dB separating their results, these two are vying for first place. For details on their systems and links to their reports, click on table (http://www.drmrx.org/forum/showthread.php?s=&postid=14421#post14421).

Congratulations, Rene and Bernd, on such great success in the propagation lottery. Conditions over there must have been so good that it was like having a tap on the transmitter's transmission line. And it's a testament to the quality and alignment of the transmitters and the receivers that such results might be achieved, if only momentarily. Well done!

73, Tom

[VE3MEO]

Rene hit 42.1 dB today - from DW Sines on 11830. Wow!

Originally posted by VE3MEO
SNIP

First it was Rene Schmitz and DW-Sines on Jan 30 and then, one day later, Bernd, DF9RB, pulling in Voice of Russia. ... For details on their systems and links to their reports, click on table (http://www.drmrx.org/forum/showthread.php?s=&postid=14421#post14421).

SNIP

[df9rb]

Hi all,

here a link to a describtion of an DRM-Receiver with optimized performance. SNR 47.4 dB!

http://www.iis.fraunhofer.de/dab/products/drmmonitoringreceiver/Paper_5th_Workshop_Digital_Broadcasting_04.pdf

Bernd, DF9RB

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=14421#post14421)

73, Tom

Feb 8: simone inched closer to the 40 dB hurdle, now within 2.1 dB at 37.9dB.

Feb 13:
Daniel, DF8UO, climbed into a tie for 5th place with hseppo at 35.7dB.

[hsseppo]

Hi Tom and all,

I am back again with a new home made receiver. I am using now AD9951 14Bit DDS and AD831 mixer. I don't have problems of spurious or image frequencies any more. Also noise level is lower than my old AD9834 + TUF-3 receiver. I think that AD831 mixer performance is very good, low noice level, good IP3.

Here is my first test of Dream -t transmitter.

>>>>
Dream
Software Version 1.1.7cvs
Starttime (UTC) 2005-02-16 20:21:19
Frequency 10012 kHz
Latitude
Longitude
Label Dream Test
Bitrate 20.96 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0000 44 150 0/10 0
0001 45 150 0/10 0
0002 45 150 0/10 0
0003 45 150 0/10 0
0004 45 150 0/10 0
0005 45 150 0/10 0
0006 45 150 0/10 0
0007 45 150 0/10 0
0008 44 150 0/10 0
0009 45 150 0/10 0

SNR min: 41.4, max: 45.8


45.8 db SNR I just can't believe it is true!
Well, the real an air signal testing is just starting.

73, Seppo

[VE3MEO]

That's impressive Seppo. What is your test transmitter system or upconverter?

It would be interesting if one could compare the % audio decoded between two receivers whose performance was identical in every respect except the max DRM SNR, so we could tell if it is worth the effort to strive for the highest max SNR in receiver design. If it turned out that the difference between a 25 dB max and a 45 dB max receiver was only 0.1% when success is over 99.5%, then it would not be worthwhile if the cost difference was significant. If it made a difference of 20% when the success rate is below 50%, who cares! The success rate is so low that we would give up trying to listen on either one.

73, Tom

Originally posted by hsseppo
Hi Tom and all,

I am back again with a new home made receiver. [snip]
45.8 db SNR I just can't believe it is true!
Well, the real an air signal testing is just starting.

73, Seppo

[hsseppo]

Hello Tom,

My test transmitter upconverter is a SA612 mixer. I am using HP Omnibook 6000 notebook computer and Dream software (linux version drm -t) to feed the mixer. Local oscillator is 10 MHz crystal oscillator. So it is very simple transmitter, just mixer and oscillator. The output of mixer is attenuated to the right level, so that receiving input level is about -10 dB.

I believe that a good SNR is not so important. My experience is that a good DRM radio must be free of interferencies. My Sony ICF-2001D receiver has very clean signal, but the PLL phase noise limits the maximum SNR to 28 dB. Clearly the new DDS receiver (AD9951+AD831, 45dB SNR) is working better. The old DDS-receiver (AD9834+TUF-3, 43dB) was sometimes much worse than Sony, beacause of DDS spurious. I even used preselector, but was not able to filter mirror and spurious frequencies. The SNR spectrum is a very good option in the Dream software. Using this option it is easy to see that a good receiver must be free of interferencies.

I think that the only usable DDS is 14 Bit AD9951. The IF must be reasonable high, I am using 21.4MHz, 15kHz 6 pole crystal filter (I would use 55 MHz, if they were easier available). Also mixer should have good third-order intermodulation and low distortion. So AD831 is a good mixer. As a bonus you get also high SNR.

At last I like to encourage to build homebrew receivers. Earlier I was afraid of small smd components, but they are really nice components and easy to use. Only a microscope (8 x) and soldering flux is needed.

Seppo

[VE3MEO]

Hi Seppo,

You did a very impressive job with the surface-mount devices.

I made a NE612 upconverter for testing at 455kHz (loopthrough the downconverter) and at 10MHz for testing the whole receiver system but did not achieve such great results.

73, Tom

Originally posted by hsseppo
Hello Tom,

My test transmitter upconverter is a SA612 mixer.
{snip}
At last I like to encourage to build homebrew receivers. Earlier I was afraid of small smd components, but they are really nice components and easy to use. Only a microscope (8 x) and soldering flux is needed.

Seppo

[Rene Schmitz]

Hi all,

First of all: Congrats Seppo! Well done!

It shows that with care, you can get on par with commercial gear.

I've made similar measurements on my modded elektor:

>>>>
Dream
Software Version 1.1.6cvs
Starttime (UTC) 2005-02-22 23:11:10
Frequency 9992 kHz
Latitude
Longitude
Label Dream Test
Bitrate 20.96 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0000 45 150 1500/10 0

SNR min: 44.0, max: 45.9

CRC:
<<<<

I had made a similar test in January, but I can't reproduce its result of over 47dB.

Bear in mind that this RX uses the AD9835 DDS, which is only 10Bit. My upconverter is a RMS11-X DBM with a 10Mhz Xtal osc.
RF and IF port of the DBM were swapped. The levels have to be very carefully adjusted to get the maximum SNR. I used the lower sideband, since then the carrier which isn't fully suppressed end up on the high frequency side, where I get a better attenuation in the IF stage, by shifting the signal of the upconverter arround (IF of dream -t). On the lower side it eventually folds to negative frequencies once it gets past 0kHz. Somehow this carrier seems to affect the SNR.

So in all, I can't fully agree that the 14Bit DDS is a must. :-)

I use that AD831 as the second mixer, and I can also say that its a very good mixer. I think over time I will make all this into a fully fledged double conversion RX, using what I have now as the IF stage. The mirror supression of 450kHz IF is way to little.

Cheers,
René

[Han]

Hello everyone

Here is my max SNR reached

I use a unmodified AOR AR 7030. On the 455 kHz AUX output i have a sat schneider converter and this is the result.
For a better result i often put the AGC at Off. I can give a 5 dB better result then when on slow

Greetings Han

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=14421#post14421)

73, Tom

Feb 9:
Han's 35.4 dB report of this date puts him onto the list in 8th place.

Mar 20:
Daniel, DF8UO, climbed 1 dB to 36.7 and 4th place.

[df9rb]

Hi all,

some posts earlier Tom asked if there would be a difference in the reception results between a receiver which can achieve very high SNR compared to another achieving only lower maximum SNR. I bought a Sangean ATS 909 some days ago to try portable DRM reception on business tripps. Today I modified this radio for DRM and did the first comparing tests between my TS850 (maximum SNR better than 40 dB) and the Sangean.
Here the first results (all tests with the same antenna):
Maximum SNR Sangean approx. 28 dB (DW from Sines 15440)
On BBCWS on 7320 there is only a little difference between both
receivers and 100% audio with both (see attachment)
The next evenings I will do some further test on more crowded frequencies and higher demands on filters and strong signal bahavior.

Bernd , DF9RB

[df9rb]

Hello,

I compared between the TS850 and the Sangean. The first screenshot shows the SNR and audio of DW from Taldom on 5830 the second BBCWS on 1296. On the 5830 there are some dropouts with the Sangean, on 1296 is only a very short dropout with the Sangean.

Bernd, DF9RB

[VE3MEO]

Originally posted by df9rb
I compared between the TS850 and the Sangean.

Hi Bernd,

I think it's a great test you're doing. Are the receivers logging at the same time or are the logs showing several minutes on one radio then several minutes on the other?

Ideally, they should be simultaneous because of changing propagation and interference. Dream allows two independent instances with one decoding from the left audio channel and the second decoding from the right.

73, Tom VE3MEO

[df9rb]

Hi Tom,

the records are done one after the other at the moment. I know that Dream can use two independent inputs but I do not have the necessary cable for two channels between the computer and the radios. Next weekend I will use my laptop from the QRL to log
simultaneous. These reports are much better comparable then.


Bernd, DF9RB

[dk8cb]

Hi Bernd,

please make sure that the RF Gain on the Sangean is not turned up too high during your tests. It is preferable to us a lower gain setting since the capability to handle large signals is usually not very good on portable receivers such as the Sangean.
On my Sangean ATS-803A, which is an older model, I set the gain (set by an attenuating potentiometer) mostly to a very low value (30%) since signal strength on 'real antennas' is usually no problem.

Roland

[df9rb]

Hi Roland,

this was the first behavior I observed when adjusting the mixer for the 12 kHz IF. I tried to adjust both equipments to the same
IF level. The AGC of the TS850 has a much higher dynamic range than the Sangean ATS909. If a signal comes out of noise a little the TS850 delivers the same input signal to the soundcard as a 9+60 signal. Using the ATS909 I have to use the the RF-Gain most of the time to adjust for correct input levels to the soundcard.
I adjusted the mixer for the Sangean to a level where the input to the soundcard reaches the optimum level receiving a weak signal and AGC ON. On stronger stations I reduce the RF-Gain of the ATS909, on very strong signals I have to reduce the sondcard mixer additionally.

I observed an other influence on the SNR of the Sangean!
With batteries the SNR is approx 3 dB higher compared to operation with the original power supply. I have wound up the 6 V cable through ferrites but this did not help too much, using a regulated power supply improves the SNR a little but the best is batteries.

Bernd, DF9RB

[dk8cb]

Hi Bernd,

have you checked that the rectifier diodes inside your Sangean power supply are shorted for RF by small capacitors, usually of 10 nF each?
This is the first modification one should apply to any power supply used with a shortwave receiver regardless which mode, DRM or AM, it will be used with. But normally, the original power supply supplied with the set should already contain such capacitors.

Roland

[df9rb]

Hi all,

here as promised the first comparison log recorded at the same time between my TS850 and the Sangean ATS 909. Both radios shared the same antenna and manually adjusted RF-gain.
The 2nd graph is the Sangean.
Interesting is the parallel characteristics of the SNR graphs.


Bernd, DF9RB

[df9rb]

Hi,

here two reports TS850-Sangean for VoR on 7390 and RTL 6095.
At the beginning of the log on 7390 I used the same antenna splitting the signal with a T-connector. I was surprised about the unexpected low SNR from VoR. At 20:40 I connected a separate antenna to every radio and the SNR increased. That means that a simple T-connector is really not the correct antenna splitter even with very strong signals. I will solder a resitive splitter the next days.

Bernd, DF9RB

[df9rb]

Hi all,

my comparative test between a receiver achieving high SNR (greater 40 dB) and a receiver achieving only 15 db lower maximum SNR is very definite: The percentage of correctly decoded audio is nearly the same! Strong stations on clear frequencies give 100 % on both. For stations with strong adjacent stations or mulitpath reception the high SNR receiver has approx. 4 % more decoded audio. If the band closes both receivers stop decoding at the same time (see attachment). Because of this "go - no go" behavior of DRM I would propose a new thread which sould be named "DRM with selectable quality by the listener " as even with better receivers the listener has no chance to follow the broadcasting then with lowered quality if the signal falls beneath the "go-level".

Bernd, DF9RB

[VE3MEO]

Originally posted by df9rb
The percentage of correctly decoded audio is nearly the same! (snip) For stations with strong adjacent stations or mulitpath reception the high SNR receiver has approx. 4 % more decoded audio.

Hi Bernd,

Great reports! In my books, 4% is not nearly the same - it's a huge difference. I think that, for the average listener, the successful audio decoding must be well above 99% to be satisfying, or to avoid driving them away. A 0.5% dropout rate is significant and may be excessive for many.

I would say that your tests do demonstrate that there is merit in seeking the higher DRM SNR performance because it does make a difference where it matters - in the 99% region. I don't think anybody cares about the difference in performance when both are well below the 99% level - they will have stopped listening! :D

73, Tom

[VE3MEO]

It's been quiet as far as new entries or advancements in the table since Mar 20! What gives? Has nobody had a better result? Are there no new members hitting 30+dB SNR? Or is this a subject that has run its course?

73, Tom

Originally posted by VE3MEO
Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=14421#post14421)

73, Tom

Feb 9:
Han's 35.4 dB report of this date puts him onto the list in 8th place.

Mar 20:
Daniel, DF8UO, climbed 1 dB to 36.7 and 4th place.

[df9rb]

Hi all,

today I did two more comparative tests between the TS850 and the Sangean ATS 909 on the same antenna and both radios with
optimized RF gain. One log is BR5akt, the other RTL Radio. BR5akt does not suffer from interference so badly as RTL Radio and on this frequency the TS850 is better. On the 6095 3 stations are interfering and there is no differnece between the two radios.
In the attachment alway the 2nd graph is the Sangean.

73s de Bernd, DF9RB

[Bob]

Hi Tom,

I know this thread is just a bit of fun really but I hit a new high (for me anyway) today. My trusty AR-88D with a Wellbrook LA5030 loop antenna hit 32.5 dB this afternoon on a DW transmission on 13790KHz . I was logging simultaneously using Dream 1.2.4 and DRM 2.034. The latter showed the max SNR as only 31.2 dB so I have attached the Dream log in preference !

I hope this lifts me off the bottom of the league table (don't want to be shown up by all those solid-state receivers) !

regards
Bob

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

This is a listing in descending SNR of reported Max DRM SNR as logged by DRMRX and Dream software, and analysed by Carknue's DRMcalc. It's for fun but might yield some useful tips for better reception. If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list. 40 dB off-air SNR has been surpassed!

Most recent entries have dB in bold.

73, Tom
<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>51.4 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9551, AD831, 21.4 IF
<td>AD831
<td>DReaM 1.2.5c
<td>Direct from Tx
<td>Dream Test
<td>10012
<td>2005-06-30 (http://www.drmrx.org/forum/showthread.php?s=&postid=18514#post18514)
<tr><td>45.1 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.3.1cvs
<td>3-el ham Yagi, ALA1530, 30m wire or EWE
<td>Voice of Russia
<td>15780
<td>2005-10-16 (http://www.drmrx.org/forum/showthread.php?s=&postid=21605#post21605)
<tr><td>42.1 dB
<td>René Schmitz, Bonn, Germany
<td>Elektor custom IF, ADA831 2nd mxr, TUF-1,1st mxr preselector
<td>
<td>DReaM 1.1.6c
<td>5m wire
<td>DW Sines
<td>11830
<td>2005-02-05 (http://www.drmrx.org/forum/showthread.php?s=&postid=14947#post14947)
<tr><td>41.9 dB
<td>FritzWue DK6QI 52N 07E
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.2.4
<td>2x 40m T up 22m
<td>DW
<td>7265
<td>2005-09-06 (http://www.drmrx.org/forum/showthread.php?s=&threadid=1072&postid=20460)
<tr><td>41.2 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>TS850 AGC inactive
<td>SA612 ceramic resonator
<td>DReaM 1.1.7c
<td>3-el ham Yagi, ALA1530, 30m wire
<td>Voice of Russia
<td>15780
<td>2005-01-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=14778#post14778)
<tr><td>40.0 dB
<td>df8uo, Karlsruhe, Germany
<td>FT757GX
<td>Sat-Schneider xtal
<td>Dream 1.3c
<td>dipole
<td>VOR
<td>15780<td>2005-10-03 (http://www.drmrx.org/forum/showthread.php?s=&postid=21210#post21210)
<tr><td>37.9 dB
<td>simone, Bad Salzschlirf, Germany
<td>FRG100 AGC off
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>11830
<td>2005-02-08 (http://www.drmrx.org/forum/attachment.php?s=&postid=15035)
<tr><td>37.6 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9551, AD831, 21.4 IF
<td>AD831
<td>DReaM 1.2.5c
<td>5m wire
<td>VoR
<td>15780
<td>2005-06-30 (http://www.drmrx.org/forum/attachment.php?s=&postid=18509)
<tr><td>36.5 dB
<td>CT1ADT, Sines, Portugal
<td>TS-870 unmodified
<td>11,3 kHz out
<td>DRM 2.0.34
<td>8m vert or 24m dipole
<td>VOR
<td>15780
<td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
<tr><td>36.3 dB
<td>carknue, Frankfurt, Germany
<td>AOR-7030 AGC off
<td>Sat-Schneider xtal
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>DW
<td>5980
<td>2005-10-14 (http://www.drmrx.org/forum/showthread.php?s=&postid=21541#post21541)
<tr><td>35.9 dB
<td>johnn, Scunthorpe, N.Lincs, UK
<td>DRT-1
<td>
<td>DReaM 1.5cvs
<td>AL1530 loop
<td>DW Sines
<td>17700
<td>2005-12-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=23725#post23725)
<tr><td>35.6 dB
<td>arniek, Muenster, Germany
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.4 dB
<td>Han, Netherlands
<td>AOR AR 7030 unmodified
<td>Sat-Schneider
<td>DReaM 1.1.7c
<td>?
<td>DW Sines
<td>11830
<td>2005-02-09 (http://www.drmrx.org/forum/showthread.php?s=&postid=15370#post15370)
<tr><td>34.9 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>Sony AN-1
<td>DW Sines
<td>17800
<td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
<tr><td>34.4 dB
<td>chemclouds, Richmond, Va, USA
<td>Icom IC-R75 AGC off
<td>
<td>DRMSWR 2.0.34
<td>30m inverted-L
<td>CBC Sackville
<td>9800
<td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
<tr><td>34.3 dB
<td>FritzWue DK6QI 52N 07E
<td>FT840
<td>Sat-Schneider
<td>DReaM 1.1.6c
<td>2x 40m LW
<td>DW-Sines
<td>17800
<td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
<tr><td>34.3 dB
<td>Kjell Holen LA6XJ Bergen, Norway
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.1.7c
<td>70 cm indoor loop
<td>Voice of Russia
<td>12060
<td>2005-01-15 e-mail
<tr><td>34.2 dB
<td>Werner DK8FT
<td>IC R71 AGC off
<td>Sat-Schneider xtal
<td>Dream 1.1.6
<td>4m wire
<td>DW-Sines
<td>17710
<td>2005-02-20 not posted
<tr><td>33.5 dB
<td>johnn, Scunthorpe, N.Lincs, UK
<td>AOR 7030
<td>
<td>DReaM 1.2.4
<td>AL1530 loop
<td>Radio Luxembourg
<td>7145
<td>2005-10-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=22124#post22124)
<tr><td>33.2 dB
<td>G3VRF, Warwickshire , UK
<td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
<td>12kHz DRM xtal ctld
<td>DReaM 1.1.6c
<td>35cm tuned loop in attic 11m a.g.
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
<tr><td>33.2 dB
<td>simone
<td>Coding Tech DWT
<td>
<td>Dream 1.2.3cvs
<td>long wire
<td>Bouquet Flevo NL
<td>7240
<td>2005-07-24 (http://www.drmrx.org/forum/showthread.php?s=&postid=19030#post19030)
<tr><td>33.0 dB
<td>Digger, CH-5023 Biberstein
<td>FRG7700
<td>SO42P xtal
<td>Dream 1.2.4
<td>12m long wire
<td>DW
<td>17800
<td>2005-11-02 (http://www.drmrx.org/forum/showthread.php?s=&postid=22347#post22347)
<tr><td>32.5 dB
<td>Bob, St Albans UK
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>Dream 1.2.4
<td>Wellbrook LA5030 indoor loop
<td>DW
<td>13790
<td>2005-05-22 (http://www.drmrx.org/forum/showthread.php?s=&postid=17414#post17414)</td></tr>
<tr><td>32.5 dB
<td>Tom VE3MEO Toronto, Canada
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>32 dB
<td>carknue, Frankfurt, Germany
<td>Coding Tech DWT
<td>
<td>Dream 1.3.1cvs
<td>Degen DE31 Active Loop
<td>DW
<td>5980
<td>2005-10-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=21315#post21315)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.4 dB
<td>TimoHannes, Petäjävesi, Finland
<td>elektor
<td>?
<td>DRMSWR 2.0.34
<td>active
<td>DW Sines
<td>17800
<td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
</table> [/B][/QUOTE]

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

May 22:
Bob's trusty old AR-88 tube radio hits 32.5 dB!

May 26:
Daniel, DF8UO, gained another dB to 37.8 with his FT757 and is nipping at the heels of simone's FRG-100 for 3rd place.

Originally posted by VE3MEO
It's been quiet as far as new entries or advancements in the table since Mar 20! What gives? Has nobody had a better result? Are there no new members hitting 30+dB SNR? Or is this a subject that has run its course?

73, Tom

[df8uo]

Hi all,

DF9RB's comparisons motivated me to perform also some comparison tests. I read a lot of the DWT, however missed real practical tests. Find below my results after having a DWT for 2 weeks now.

Today i made a comparison of the DWT and FT757GX, using the VOR signal on 15780kHz.I was using two different antnnas. Antenna 1: Dipole 2x5m Antenna 2: Shortened trap dipole (for 10, 15, 20m).
Antenna 1 gives in general better DRM results. Attached the reults:
DWT(red/blue) 9h00-10h00 Antenna 1; 10h00-11h00: Antenna 2
FT757 (green/yellow) 9h00-10h00 Antenna 2; 10h00-11h00: Antenna 1
Signal of VOR on the FT757 was S5-S9 with antenna 2 and S8 to S9+ with antenna 1. The comparison showed me, that my FT757 can handle adjacent channel interference much better than the DWT. On 15785 a partly quite strong signal was present (probably Radio Galei Tzahal from Israel). The AM filter of the FT757 is a little to small for DRM, which for these cases has also advantages. From all the experiments up to know i could see that SNR on my FT757 under similar conditions is 3 to 10 dB better
than the DWT. If i compare weight and size of the DWT and my FT757, this small device is quite good.
The most critical point for the DWT is the usage of provisorical wire antennas. Here i will do some further experiments. Using dipole antennas are performing quite well.

Some examples for the DWT and antenna 2 you can find here:
<p><a href="http://www.drmrx.org/forum/showthread.php?s=&amp;postid=18302#post18111">ORF 6155: </a><br>
<a href="http://www.drmrx.org/forum/showthread.php?s=&amp;postid=18304#post18304">DW 7390</a>: <br>
<a href="http://www.drmrx.org/forum/showthread.php?s=&amp;postid=18287#post18123">BBC 7320</a> <br>
<a href="http://www.drmrx.org/forum/showthread.php?s=&amp;postid=18321#post18306">Mighty 5830</a> <br>
<a href="http://www.drmrx.org/forum/showthread.php?s=&amp;postid=18321#post18299">Mighty 7430</a> </p>

More to come.

73, Daniel

[hsseppo]

Hi Tom and all,

Building a DRM-receiver has been very educational for me. Especially measuring the specs like the mixer 1dB compression point and the intercept point. I used two-tone technique to measure the third-order distortion. My AD831 mixer compression point was +(8-9) dBm (abt. 1.6 Vp-p) and IP3 about +(15-18) dBm. Using the two-tone method it was easy to see that at level 0dBm 3rd order output was -25 dBm and at level -10 dBm 3rd order was -55 dBm. At level +4dBm 3rd order was only -16 dBm and at +8dBm input level the distance of 3rd order was about 10 dB.

When RF input increases 10dB 3rd order increases 30dB!
It looks like the 3rd order distortion is a very important factor for DRM performance. My Sony ICF-2001D receiver has about 35dB distance of 3rd order, maybe this is the reason for the low maximum 28dB SNR and not the PLL phase noise.

As I have a AD8099 preamplifier (44dB gain) feeding the AD831 mixer, the input RF levels of my receiver are: -36dBm to -126 dBm (10 mVp-p to 0.3 uVp-p).

Next I measured the maximum SNR, feeding dream -t to SA612 mixer and got 50 dB SNR.

>>>>
Dream
Software Version 1.2.5cvs
Starttime (UTC) 2005-06-30 11:34:32
Frequency 10012 kHz
Latitude
Longitude
Label Dream Test
Bitrate 20.96 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0000 50 150 1500/10 0
0001 50 150 1500/10 0
0002 50 150 1500/10 0
0003 50 150 1500/10 0
0004 50 150 1500/10 0
0005 51 150 1500/10 0
0006 51 150 1500/10 0
0007 51 150 1500/10 0
0008 51 150 1500/10 0
0009 51 150 1500/10 0
0010 51 150 1500/10 0
0011 50 150 1500/10 0

SNR min: 49.0, max: 51.4

CRC:
<<<<


It was also a lucky day for me, as I got my record 37.6 dB SNR from 15780 kHz (Voice of Russia)

http://www.drmrx.org/forum/showthread.php?s=&postid=18509#post18509

Best Regards,

Seppo

[Rene Schmitz]

Hi Seppo and all,

Congrats to your archeivement! 51dB even in the lab, thats something!

Not difficult to imagine what happens when the mixer is overdriven, instead of two tones you have the 100+ carriers intermodulating each other. I have made similar observations with my mods for the Elektor RX. Most of which focussed around getting more gain but also more linearity out of the IF stage and the final mixer. (If anyone is interested, the IF amp I built has been published here (http://hamburg096.server4you.de/~rene/drm/drmmod_en.pdf)
) The original crummy FET-mixer of the RX was later changed to an AD831, but finally again to a ring mixer. While I'd clearly favour the AD, now that I made the comparison, its probably staying that way for a while.

Cheers,
René

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

June 30:
Two big moves for Seppo (hsseppo) using his revised modular receiver:
a) 51.4 dB in closed circuit test (I included this because it indicates nearly ideal conditions that might occasionally be realisable from a real system comprising a powerful transmitter and perfect propagation! If anyone achieves a higher test result, it will replace this one as a point of reference.

b) 37.6 dB with this receiver pulling in VoR - 5th place among actual reception reports.

July 2:
Fritz Wue's (DK6QI) new Sat-Schneider DRT1 radio achieved 37 dB - 6th place and 2.6 dB better than his previous best with his FT840

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

July 18:
Fritz Wue (DK6QI) vaulted from 6th to 3rd place with his new Sat-Schneider DRT1 radio achieving 39.3 dB, 2.3 dB better than his previous best! Now he is just 0.7 dB away from the rarified atmosphere at 40 dB and above where only two have ascended so far under real (non-lab) conditions.

[df9rb]

Hi all,

I built the up-mixer described by hsseppo and Seppo sent me a CD with the DRM testsignals (again thanks to Seppo). First of all: if you build this mixer also do not connect the capacitor at the input between the input and the potentiometer. The correct placement is between pin 1 and the potentiometer! I think pin 1 must be floating as pin 2. I did not get any modulation at the output with the original schematic.
Here first results:
audio fed directly to the sound card: SNR 55 dB
DRM signal via the up-mixer to my TS850: SNR 44 dB
The SNR via the up-mixer is very level sensitive above a SNR of 35 dB. Now I will try to optimize the level chain (up-mixer, manual Gain control of the TS850, level to the 12 kHz mixer, input level of the soundcard). Perhaps I can also achieve the 50 dB boarder.

73s Bernd, DF9RB

[df9rb]

Hi all,

I made some additional tests with the DRM-signal directly fed to my TS850 via an up-mixer. Here the results:
- activated Bandpass Filter in Dream always deliveres the best SNR
- Modified Metrics has no influence
- Number of Iterations has no influence
- default settings of Channel Estimations and Time Sync are the best
- Input Level -10 dB is the best (even though this is displayed in red)
- the 6 kHz Filter!!! is the best even though the Input PSD is strongly attenuated at the edges
- it is better to adjust higher amplification of the soundcard input and reduce the level at the 12 kHz down-mixer.
- high SNR is very level sensitive
- the maximum SNR of the TS850 is 44.5 dB varying 1 dB even under this stable "lab"-conditions

I also connected the up-mixer (12 to 467 kHz) output to the down mixer (467 to 12 kHz) input to determine the possible SNR of the mixer itself. This don t work!. At the up-mixer output the carrier, upper and lower sideband is delivered. These signals modulate the down-mixer and no decodeable DRM signal is available anymore.

Next I will test my Sangean

Bernd, DF9RB

[df9rb]

Hi all,

now I determined the max SNR of my Sangean ATS909. The picture shows 4 modi:
- supplied by batteries, manual gain control - SNR 28.5 dB
- supplied by batteries, AGC - SNR 22 dB
- supplied by the original Sangean power supply, manual - SNR 22 dB
- Power supply, AGC - SNR 20.5 dB
Till the end of the diagramm again with batteries and manually adjusted
Every measurement was done at - 10 dB input level to the soundcard.

Bernd, DF9RB

[FritzWue]

- the 6 kHz Filter!!! is the best even though the Input PSD is strongly attenuated at the edges

Hi Bernd,

found the same here when modifying my Yaesu FT-840.
The narrow CFW455HT filter with -6dB/6kHz gave best results, especially under adjacent interference conditions.

[hsseppo]

Hi,

as there has been some questions about my upconverter, I include the schematics on this thread.
To get a high SNR source I made a CD using the following method:
My soundcard is Terratec 24/96 EWX and I have Steinberg WaveLab Lite software. So I used Dream -t with sound out to EWX 24/96 wave audio and WaveLab Lite was recording 12kHz audio on disk. Then I made 30 minute recording and burned adio.wav on CD-rom. I used a standard CD-player to feed my up-converter. When CD output is connected direct to PC audio input I get 61.8 dB SNR. If I use EWX 24/96 S/PDIF my SNR is 66.0 dB

73s Seppo.

Thanks to Bernd, he noticed my mistake in the dream-up-converter. Now it should be ok.

[df9rb]

Hi,

I tested the DRT1 from Sat-Schneider with a signal from an upconverter and the DRM-CD from hsseppo.
The DRT1 delivers an amazing SNR of 47 dB!
(the varying of the SNR are caused by some alignment trials)

Bernd, DF9RB

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

Aug 15:
Fritz Wue (DK6QI) made 39.9 dB with his DRT1 radio, a 0.6dB gain from July 18. more (http://www.drmrx.org/forum/showthread.php?s=&postid=19585#post19585)

Aug 23:
Fritz breaks through 40 dB with a bang! 41 dB peak SNR. more (http://www.drmrx.org/forum/showthread.php?s=&postid=19842#post19842)

Sep 9: a BIG day!
Fritz hits 41.9 dB from DW on 7265 kHz... more (http://www.drmrx.org/forum/showthread.php?s=&threadid=1072&postid=20460) and more (http://www.drmrx.org/forum/attachment.php?s=&postid=20460)

Bernd (DF9RB) blazed into first place with 43.6 dB from VoR on 15780 kHz on his DRT1! more (http://www.drmrx.org/forum/showthread.php?s=&postid=20447#post20447).

Looks like the DRT1 is the highest SNR commercial receiver on the chart.

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

Oct 3: Daniel, DF8UO, joins the rare ranks of the off-air 40dBers, bringing the count to 5 reported!

The last two months have seen dramatic results - thanks to the DRT1 in many cases, perhaps general learning and optimisation at both senders and receivers, and maybe propagation. We have seen hsseppo do a loopback test attaining 51.4 dB so it's possible that we will see some advance yet on DF9RB's 43.6dB off-air.

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

Oct 14: Carsten (carknue) advanced two positions in the table with a new best of 36.3dB with his AOR7030. He also achieved 32dB with his new Digital World Traveller from Coding Technologies and Degen DE31 active loop antenna.

With the surpassing of the 40dB mark, Carsten has revised the ceiling of the graphical scale on his excellent DRMcalc software to 44dB. I'll bet that's surpassed this winter! DF9RB has come within a 1/2 dB.

[df9rb]

Hi Tom,

during reading your post I logged VoR. So fast you won your bet!
Peak SNR today was 44.5 dB with the DRT1
As DRM technics is continuously improving on transmitter and
receiver side I propose (or even bet 1 Dollar or so) that the 50 dB-limit will have been exceeded in 3 years on over the air signals.
- hsseppo reached 51.4 dB direct from TX
-my 96 kHz/24 bit soundcard with modified Dream for 96 kHz sampling rate is good for more than 60 dB SNR
- my DRT1 reached 47 dB direct from TX, with the limiter during this test beeing very likely the used up-mixer

Bernd, DF9RB

[df9rb]

Hi all,

44.5 was not the end today. During the transmission from Taldom on 15780 kHz in German SNR climbed up to 45.1 dB.
I used this excellent condx to compare between Dream with 48 kHz sample rate and the modified version for 96 kHz. The result is marginal: under rough conditions no better decoding with 96 kHz; up to 40 dB no difference, above 40 dB the SNR with 96 kHz sampling rate is 0.1 better to 0.2 dB at 45 dB. The soundcard is a Sound Blaster Live! 24-bit. The CPU load is very high however even with the AMD 3400+ running Dream and sound card in 96 kHz/ 24 bit.

Bernd, DF9RB

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

With the surpassing of the 40dB mark, Carsten has revised the ceiling of the graphical scale on his excellent DRMcalc software to 44dB. I'll bet that's surpassed this winter! DF9RB has come within a 1/2 dB.
No sooner said than done!

Oct 16: Bernd, DF9RB, leaps past the DRMcalc 44 dB ceiling with a peak of 45.1 dB!

One wonders what the ionosphere looks like when such excellent results are obtained. Is it like a mirror in the shape of a modified ellipsoid, static in elevation so there is no doppler or jitter, with the transmitter and receiving locations at equal distance for all paths, so there is no impulse spreading?

Oct 7: Carsten puts the Coding Technologies DWT into the table for the first time with 32 dB.

[simone]

Hi Tom,
I had e mailed you in June about the DWT, I think the best until now was this one:
http://www.drmrx.org/forum/attachment.php?postid=19030
Simone

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

Earlier report over 30 dB for the DWT:

July 24: Simone's best of 33.2 dB (sorry for missing this, Simone)

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showthread.php?s=&postid=17419#post17419)

73, Tom

2005-12-31 35.9 dB by johnn, Scunthorpe, N.Lincs, UK DRT-1
2005-11-02 33.0 dB by Digger, CH-5023 Biberstein FRG7700
2005-10-29 33.5 dB by johnn, Scunthorpe, N.Lincs, UK AOR 7030

[Han]

Hello everyone

I also had a quite good result
It is my best result sofar.
Sines gives me the best results most times

Receiver AOR 7030 with 455 to 12 kHz converter SAt schneider
Dream 1.5 antenne : ALA 1530

Best Dx

Han
The netherlands

[johnn]

Hello Han,
A good result that!

[Han]

Hello John

Thank you for thr reply!
I also found it a very good result, sometimes the SNR is a few days higher than normal.
I get the best results on my loop antenna, it gives a better result then my T2FD. On AM the T2FD sound most of the time better.

I think that is strange.

The best results I get from Sines, the SNR is mosttimes above 30 dB

Greetings Han

[Saulius]

Greetings

May be interesting info about my IQ DRM Decoder and
minimal Shifted PSD by Dream

http://drm.sourceforge.net/forums/index.php?showtopic=156&st=0&#entry874


Best regards

Saulius

[Funkerberg]

This is my best result so far.

Receiver : Elektor
antenna : selfmade 10 m Dipol
QTH: Königs Wusterhausen / 20 km south of Berlin / Germany

many greetings Rainer

[Digger]

Hi,

Still not the best but a personal best. The FRG 7700 with a 7808 in the Vcc supply helped a bit. Using an external 17 Volt DC power supply instead of the receiver's AC / DC supply improved SNR considerably. Some level adjustment into the S042P on the IF side brought some improvement too. The last change (so far) was the 10 µF capacitor for slow AGC that got another 47 µF in parallel.

This morning I listened to DW on 13810 kHz and got a max. of 34,2 dB SNR.

Dream
Software Version 1.5cvs
Starttime (UTC) 2006-04-05 08:08:09
Frequency 13810 kHz
Label Deutsche Welle
Bitrate 17.26 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0016 30 150 1500/10 0
0017 31 150 1500/10 0
0018 33 150 1500/10 0
0019 34 150 1500/10 0
0020 33 150 1500/10 0
0021 33 150 1500/10 0
0022 34 150 1500/10 0
0023 34 150 1500/10 0
0024 34 150 1500/10 0
0025 32 150 1500/10 0
0026 33 150 1500/10 0
0027 32 150 1500/10 0
0028 32 150 1500/10 0


SNR min: 4.9, max: 34.2


Terje

[VE3MEO]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

This is a listing in descending SNR of reported Max DRM SNR as logged by DRMRX and Dream software, and analysed by Carknue's DRMcalc. It's for fun but might yield some useful tips for better reception. If you have results that leap the 30 dB hurdle, e-mail me with the details and I'll add it to the list. 40 dB off-air SNR has been surpassed!

Most recent entries have dB in bold.

73, Tom
<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>51.4 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9551, AD831, 21.4 IF
<td>AD831
<td>DReaM 1.2.5c
<td>Direct from Tx
<td>Dream Test
<td>10012
<td>2005-06-30 (http://www.drmrx.org/forum/showthread.php?s=&postid=18514#post18514)
<tr><td>48.3 dB
<td>mitajohn Athens, Greece
<td>Sat-Schneider DRT1
<td>
<td>Dream 1.6.1 cvs
<td>Dream -t burnt CD played into SA602 up-mixer
<td>test
<td>1000
<td>2008-02-09 (http://www.drmrx.org/forum/showpost.php?p=45729&postcount=103)
<tr><td>48 dB
<td>DRM-OM (Bernhard), 25km SE Karlsruhe Germany
<td>Sat-Schneider DRT1
<td>
<td>Fraunhofer IIS software radio V4.0.40
<td>Direct from Tx
<td>Test
<td>6000
<td>2006-04-24 German (http://privat.albicker.org/kurzwelle-drm/umbau-drt1.html), English Translation (http://translate.google.com/translate?u=http%3A%2F%2Fprivat.albicker.org%2Fkur zwelle-drm%2Fumbau-drt1.html&langpair=de%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools)
<tr><td>45.1 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.3.1cvs
<td>3-el ham Yagi, ALA1530, 30m wire or EWE
<td>Voice of Russia
<td>15780
<td>2005-10-16 (http://www.drmrx.org/forum/showthread.php?s=&postid=21605#post21605)
<tr><td>42.1 dB
<td>René Schmitz, Bonn, Germany
<td>Elektor custom IF, ADA831 2nd mxr, TUF-1,1st mxr preselector
<td>
<td>DReaM 1.1.6c
<td>5m wire
<td>DW Sines
<td>11830
<td>2005-02-05 (http://www.drmrx.org/forum/showthread.php?s=&postid=14947#post14947)
<tr><td>42.0 dB Euro bonus:D
<td>FritzWue DK6QI 52N 07E
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.6.1cvs
<td>80m dipole up 20m
<td>DW
<td>13810
<td>2006-09-09 (http://www.drmrx.org/forum/showpost.php?p=30863&postcount=129)
<tr><td>41.2 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>TS850 AGC inactive
<td>SA612 ceramic resonator
<td>DReaM 1.1.7c
<td>3-el ham Yagi, ALA1530, 30m wire
<td>Voice of Russia
<td>15780
<td>2005-01-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=14778#post14778)
<tr><td>40.6 dB
<td>DG9BFC, Barenburg, Germany
<td>IC-765 manual gain
<td>Sat-Schneider xtal
<td>Dream 1.6.1cvs
<td>170m delta loop
<td>DW Sines
<td>13810<td>2006-09-26 (http://www.drmrx.org/forum/showpost.php?p=31316&postcount=95)
<tr><td>40.4
<td>FritzWue DK6QI 52N 07E
<td>Flex-5000A
<td>
<td>DReaM 1.6.1cvs
<td>80m dipole up 20m
<td>DW Moosbrunn
<td>7310
<td>2008-04-19 (http://www.drmrx.org/forum/showthread.php?p=47487#post47487)
<tr><td>40.3
<td>maxpower Oldenburg, Germany
<td>Pappradio dvlpd by Stephan
<td>
<td>DReaM 1.10.6cvs
<td>longwire
<td>DW Moosbrunn
<td>7310
<td>2008-07-04 (http://www.drmrx.org/forum/showpost.php?p=49244&postcount=110)
<tr><td>40.0 dB
<td>df8uo, Karlsruhe, Germany
<td>FT757GX
<td>Sat-Schneider xtal
<td>Dream 1.3c
<td>dipole
<td>VOR
<td>15780<td>2005-10-03 (http://www.drmrx.org/forum/showthread.php?s=&postid=21210#post21210)
<tr><td>39.1 dB
<td>Digger, CH-5023 Biberstein
<td>FRG7700 + Stabilock 4040 LO
<td>SO42P xtal
<td>Dream 1.6.1cvs
<td>16m LW + 1:1 un-un
<td>DW
<td>13810
<td>2006-09-23 (http://www.drmrx.org/forum/showpost.php?p=30890&postcount=93)
<tr><td>39.1 dB
<td>mitajohn Athens, Greece
<td>Sat-Schneider DRT1
<td>
<td>Dream 1.6.1 cvs
<td>Inverted "L" 9V/16H m
<td>MOI Kuwait
<td>13620
<td>2008-05-11 (http://www.drmrx.org/forum/showpost.php?p=48067&postcount=167)
<tr><td>37.9 dB
<td>simone, Bad Salzschlirf, Germany
<td>FRG100 AGC off
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>11830
<td>2005-02-08 (http://www.drmrx.org/forum/attachment.php?s=&postid=15035)
<tr><td>37.8 dB
<td>Francois, Petite Rosselle, Fr.
<td>ELAD FDM77 AGC SW + SLOW
<td>
<td>Dream 1.6.1cvs
<td>Twin Zepp
<td>DW
<td>13810
<td>2006-11-17 (http://www.drmrx.org/forum/showpost.php?p=33193&postcount=194)
<tr><td>37.6 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9551, AD831, 21.4 IF
<td>AD831
<td>DReaM 1.2.5c
<td>5m wire
<td>VoR
<td>15780
<td>2005-06-30 (http://www.drmrx.org/forum/attachment.php?s=&postid=18509)
<tr><td>37.5 dB
<td>Han, Netherlands
<td>AOR AR 7030 unmodified
<td>Sat-Schneider
<td>DReaM 1.5cvs
<td>ALA 1530
<td>DW Sines
<td>17700
<td>2006-01-21 (http://www.drmrx.org/forum/attachment.php?attachmentid=17536&d=1138526798)
<tr><td>36.5 dB
<td>CT1ADT, Sines, Portugal
<td>TS-870 unmodified
<td>11,3 kHz out
<td>DRM 2.0.34
<td>8m vert or 24m dipole
<td>VOR
<td>15780
<td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
<tr><td>36.3 dB
<td>carknue, Frankfurt, Germany
<td>AOR-7030 AGC off
<td>Sat-Schneider xtal
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>DW
<td>5980
<td>2005-10-14 (http://www.drmrx.org/forum/showthread.php?s=&postid=21541#post21541)
<tr><td>35.9 dB
<td>johnn, Scunthorpe, N.Lincs, UK
<td>DRT-1
<td>
<td>DReaM 1.5cvs
<td>AL1530 loop
<td>DW Sines
<td>17700
<td>2005-12-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=23725#post23725)
<tr><td>35.9 dB
<td>Funkerberg, Königs Wusterhausen, near Berlin
<td>Elektor
<td>
<td>Dream 1.6.1cvs
<td>10m dipole
<td>DW
<td>5810
<td>2006-03-04 (http://www.drmrx.org/forum/attachment.php?attachmentid=18960&d=1141639182)
<tr><td>35.6 dB
<td>arniek, Muenster, Germany
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.2 dB
<td>fibber - Salem, Oregon USA
<td>Yaesu FT-817, 10dB Radio Shack preamp, NCL MW Filter
<td>I5XWW 455k to 12k board
<td>Dream 1.6.1c
<td>80M Dipole
<td>RNW
<td>6130
<td>2008-02-07 (http://www.drmrx.org/forum/showpost.php?p=45683&postcount=99)
<tr><td>34.9 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>Sony AN-1
<td>DW Sines
<td>17800
<td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
<tr><td>34.4 dB
<td>chemclouds, Richmond, Va, USA
<td>Icom IC-R75 AGC off
<td>
<td>DRMSWR 2.0.34
<td>30m inverted-L
<td>CBC Sackville
<td>9800
<td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
<tr><td>34.3 dB
<td>FritzWue DK6QI 52N 07E
<td>FT840
<td>Sat-Schneider
<td>DReaM 1.1.6c
<td>2x 40m LW
<td>DW-Sines
<td>17800
<td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
<tr><td>34.3 dB
<td>Kjell Holen LA6XJ Bergen, Norway
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.1.7c
<td>70 cm indoor loop
<td>Voice of Russia
<td>12060
<td>2005-01-15 e-mail
<tr><td>34.2 dB
<td>Werner DK8FT
<td>IC R71 AGC off
<td>Sat-Schneider xtal
<td>Dream 1.1.6
<td>4m wire
<td>DW-Sines
<td>17710
<td>2005-02-20 not posted
<tr><td>33.5 dB
<td>johnn, Scunthorpe, N.Lincs, UK
<td>AOR 7030
<td>
<td>DReaM 1.2.4
<td>AL1530 loop
<td>Radio Luxembourg
<td>7145
<td>2005-10-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=22124#post22124)
<tr><td>33.2 dB
<td>G3VRF, Warwickshire , UK
<td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
<td>12kHz DRM xtal ctld
<td>DReaM 1.1.6c
<td>35cm tuned loop in attic 11m a.g.
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
<tr><td>33.2 dB
<td>simone
<td>Coding Tech DWT
<td>
<td>Dream 1.2.3cvs
<td>long wire
<td>Bouquet Flevo NL
<td>7240
<td>2005-07-24 (http://www.drmrx.org/forum/showthread.php?s=&postid=19030#post19030)
<tr><td>32.5 dB
<td>Bob, St Albans UK
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>Dream 1.2.4
<td>Wellbrook LA5030 indoor loop
<td>DW
<td>13790
<td>2005-05-22 (http://www.drmrx.org/forum/showthread.php?s=&postid=17414#post17414)</td></tr>
<tr><td>32.5 dB
<td>Tom VE3MEO Toronto, Canada
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>32 dB
<td>carknue, Frankfurt, Germany
<td>Coding Tech DWT
<td>
<td>Dream 1.3.1cvs
<td>Degen DE31 Active Loop
<td>DW
<td>5980
<td>2005-10-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=21315#post21315)
<tr><td>31.2 dB
<td>DRM-OM, 25km SE Karlsruhe, Germany
<td>DRT-1
<td>
<td>Dream 1.6.1cvs
<td>Dressler ara100 active ant.
<td>Radio Luxembourg
<td>7295
<td>2006-04-25 (http://www.drmrx.org/forum/showpost.php?p=27082&postcount=91)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.4 dB
<td>TimoHannes, Petäjävesi, Finland
<td>elektor
<td>?
<td>DRMSWR 2.0.34
<td>active
<td>DW Sines
<td>17800
<td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
</table> [/B]

[Digger]

Hi,

Same configuration as on the 5th April. Max. 38,5 dB SNR.

Dream
Software Version 1.5cvs
Starttime (UTC) 2006-04-10 07:17:46
Frequency 7265 kHz
Latitude 47°25'N
Longitude 8°05'E
Label Deutsche Welle
Bitrate 17.26 kbps
Mode B
Bandwidth 10 kHz
MINUTE SNR SYNC AUDIO TYPE
0010 33 150 1500/10 0
0011 34 150 1499/10 0
0012 34 150 1500/10 0
0013 37 150 1500/10 0
0014 31 150 1500/10 0
0015 31 150 1500/10 0
0016 33 150 1499/10 0

SNR min: 0.6, max: 38.5

Regards,
Terje

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88)

73, Tom

2006-04-10 38.5 dB by Digger, CH-5023 Biberstein, FRG7700 modified
2006-04-18 32.4 dB by fibber - Salem, Oregon USA, Yaesu FT-817

[DRM-OM]

using DRT-1 at active antenna Dressler ara100:

>>>>
Dream
Software Version 1.6.1cvs
Starttime (UTC) 2006-04-25 13:58:25
Frequency 7295 kHz
Latitude 48°53'N
Longitude 8°31'E
Label Radio Luxembourg
Bitrate 20.96 kbps
Mode B
Bandwidth 10 kHz

MINUTE SNR SYNC AUDIO TYPE
0000 30 150 1500/10 0
0001 30 150 1500/10 0
0002 30 150 1500/10 0
0003 28 150 1500/10 0

SNR min: 27.2, max: 31.2

CRC:
<<<<

Looks fine...

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88)

73, Tom

2006-04-25 31.2 dB by DRM-OM, 25km SE Karlsruhe, Germany, DRT-1
2006-07-10 33.3 dB new high by fibber - Salem, Oregon USA, Yaesu FT-817
PLUS
DRM-OM's 48 dB test report on the DRT-1

[Digger]

Hi,

DW on 13.810 MHz is a challenge for high SNR results. Today, 10th September, I put another 0.5 dB to my previous record of 38.5 dB.

The receiver: Yaesu FR7700
Antenna: 16 meter Long Wire, and an UN-UN to 50 Ohm coax.
The first Local Oscillator: 61.865 MHz at +3 dBm (Stabilock 4040)
455 kHz output: Secondary winding of T13
12 kHz Mixer: Siemens S042P
DRM Receiver: Dream
Software Version: 1.6.1cvs
Starttime (UTC): 2006-09-10 08:00:00
Latitude 47°25'N
Longitude 8°05'E
Label Deutsche Welle
Bitrate 17.10 kbps
Mode B
Bandwidth 10 kHz
SNR min: 19.1, max: 39.0

Some interesting points regarding the FRG7700:

1. Use an external 16-17 Volt DC supply instead of the 220/240 VAC
2. Add 47 uF in parallel to the 10 uF in the "SLOW" AGC position.
3. Use an antenna tuner in the coax line to the receiver.
4. Be sure to use SLOW (in my case VERY slow AGC). Compared to the NORMAL AGC, SNR increases by 10 dB(!) See enclosed picture.
5. (For fanatics): Use an external signal generator for the 1st Local Oscillator. There is a connection between the RF input signal level and the Local Oscillator level. The record was achieved with +3 dBm from the S.G. and the RF Gain very slightly reduced.

My PC:
Intel Pentium 4 at 2.4 GHz
Windows 2000 SP4
512 kb RAM
Sound Card: Avance AC'97 Audio
Input: Line


Cheers

Terje


PS: 13.810 MHz today, 23rd Sep. 2006, max. 39,1 dB NNR

[FritzWue]

DW Sines 13810 kHz is also the best signal for me with max. 42.0 dB SNR at the moment.
I could add 0.1 dB to my highest SNR table value:
http://www.drmrx.org/forum/showthread.php?p=30863#post30863

[DG9BFC]

max snr 40.6 with icom ic765 and mixer board by sat schneider
agc controlled by hand (slow agc gives 5db lower snr)
24535

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88)

73, Tom

2006-09-09 42.0 dB a 1/10 dB improvement by FritzWue, Germany, DRT-1
2006-09-26 40.6 dB new entry with a bang by DG9BFC, Barenburg, Germany, IC-765
2006-09-23 39.1 dB new high from Digger, Biberstein, FRG-7700 with outboard 1st LO
2006-10-19 34.1 dB new high by fibber - Salem, Oregon, USA, Yaesu FT-817

[François]

Hallo all user from ELAD FDM77 HF RECEIVER (DRM),

I have find the solution to obtain the max on SNR with this receiver. In first time , you choose DRM INT in the software SETUP with validation, after ADV, AGC SW and SLOW, return on the ELAD SOFTWARE, choose SETUP, choose DRM EXT, MLC 4 and AGC off in the Dreamsoftware. Before use this procedure I have only 32 dB (DW 13810Khz) on my doubble zeppelin and now I have an SNR 36dB. Good luck to the user. In spring 2006 ELAD have send me an email and announced a SNR MAX 50 dB.

49°12'44''N
06°51'30''E

Vy 73 de François

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88)

73, Tom

2006-11-17 37.8dB a new entry and big number from Francois, Petite Rosselle, France and the first reported for the ELAD FDM77 receiver.

[fibber]

I hit a milestone in North America (I think)!

35.2dB SNR for RNW 6130kHz 20080207 @ 0529z

Current setup: Yaesu FT-817 (AGC off), R-7 vertical, DReaM 1.6.1, I5XWW board.

[FritzWue]

Chris, congrats! :D

[VE3MEO]

Indeed, congratulations, Chris! Yours is the first report of a new high in 15 mos, it seems.

I have not been active - antennas are down. I do have a FT-817 in addition to the DX-394's but have not added a converter to it. It's encouraging to see that it has good enough phase stability to deliver such a good drm snr.

73 Tom VE3MEO

[VE3MEO]

Here are the latest changes to the table. (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88)

73, Tom

2008-02-07 35.2dB a 1.1 dB jump for Chris (fibber) in Oregon with his FT-817

[mitajohn]

Hi all,

This is not a big deal, but testing my (problematic !) DRT-1, I got in "home-lab" conditions >48 dB SNR using a Dream -t burnt CD, an ordinary CD-player and a SA602 up-mixer on 1 MHz. So just for the record please up-date the table.

[simone]

Hi Tom,
seems a Winradio has not been mentioned yet, here is my screenshot from a VT digital transmission/ Woofferton using Dream 1.10.unst2 and a G313i.
Simone

[FritzWue]

Hi Simone,

wow, the G313i seems to be a lot better than my G303i! :eek:
I never saw anything even close to 30dB with my older model. :(

[suraj]

Suraj - Bangalore, India

29dB from DW

[VE3MEO]

Suraj - Bangalore, India

29dB from DW
Congratulations Suraj. When you get reception exceeding 30 dB SNR, I'd be pleased to add your report to the table (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88). You need to provide some evidence like a report from DRMCalc plus details of your equipment. There are lots of examples you can follow in the table.

Tom

[FritzWue]

Hi Tom,

the Flex-5000A has joined the >40dB SNR club, details in the DRMcalc:
http://www.drmrx.org/forum/showthread.php?p=47487#post47487
:)

[mitajohn]

Hi All,

@ Fritz, very well done my friend! My top record until now was with DRT1 from 13620 KHz at 39.1 dB SNR and in the "lab" at better than 48 dB...
@ Tom, apropos of what you were saying take a look at the following, my post 167,
http://www.drmrx.org/forum/showthread.php?p=48970#post48970 and my post 103 in this thread, hoping for a table update...

[maxpower]

Hi Tom and all!

I got about 40.26 dB SNR on a "real world" transmission with a little low cost SDR Device (less than 30 €, Soundcard type SDR & PLL controlled by serial port) that I'm currently developing for HCJB's test transmissions to europe and South America (but, of course, it can be used at any LF/MF & HF frequency, too).

http://www.drmrx.org/forum/attachment.php?attachmentid=42585&d=1215159013

Maybe you can add hat device called "Pappradio" in the list, too?`That would be very nice.


Stephan

[VE3MEO]

Congratulations to Friedrich, John and Stephan for those impressive results, the new hardware and keeping the faith.

I apologise if I was slow updating the table (http://www.drmrx.org/forum/showpost.php?p=26518&postcount=88). I'm not currently active listening to DRM or any SW so have not been active in the forum. If anyone would like to take over maintenance of the table, I'd be happy to send you the HTML source so you could post it as your own message.

Tom

[mitajohn]

Hi Tom,

Thanks for the update. On my post 103, in this thread, I forgot to mention the Dream version, which is 1.6.1 cvs.

[simone]

Hi Tom,
please send me the source file of the table and I will keep it updated.
Thanks for your work in the past.
Simone

[mvs sarma]

Hi Tom,

Thanks for the update. On my post 103, in this thread, I forgot to mention the Dream version, which is 1.6.1 cvs.
Hi, John,
Is there any pre-compiled Dream version as update to ver1.6.1.cvs ?

[mitajohn]

Hi mvs sarma,

You can find the latest here:
edit:
no links to compiled Dream versions on this forum please
Simone

[mvs sarma]

Thanks
John and I shall manage with 1.6.1cvs

[simone]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

added: FritzWue, 41.4 dB using a Flex-5000A Rx


<table align=LEFT border="1">
<tr><th>Max SNR
<th>By
<th>Receiver
<th>Converter
<th>App
<th>Antenna
<th>Service
<th>Freq(kHz)
<th>Date</th>
<tr><td>51.4 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9551, AD831, 21.4 IF
<td>AD831
<td>DReaM 1.2.5c
<td>Direct from Tx
<td>Dream Test
<td>10012
<td>2005-06-30 (http://www.drmrx.org/forum/showthread.php?s=&postid=18514#post18514)
<tr><td>48.3 dB
<td>mitajohn Athens, Greece
<td>Sat-Schneider DRT1
<td>
<td>Dream
<td>Dream -t burnt CD played into SA602 up-mixer
<td>test
<td>1000
<td>2008-02-09 (http://www.drmrx.org/forum/showpost.php?p=45729&postcount=103)
<tr><td>48 dB
<td>DRM-OM (Bernhard), 25km SE Karlsruhe Germany
<td>Sat-Schneider DRT1
<td>
<td>Fraunhofer IIS software radio V4.0.40
<td>Direct from Tx
<td>Test
<td>6000
<td>2006-04-24 German (http://privat.albicker.org/kurzwelle-drm/umbau-drt1.html),

English Translation (http://translate.google.com/translate?u=http%3A%2F%2Fprivat.albicker.org%2Fkur zwelle-drm%2Fumbau-drt1.html&langpair=d

e%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools)
<tr><td>45.1 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.3.1cvs
<td>3-el ham Yagi, ALA1530, 30m wire or EWE
<td>Voice of Russia
<td>15780
<td>2005-10-16 (http://www.drmrx.org/forum/showthread.php?s=&postid=21605#post21605)
<tr><td>42.1 dB
<td>René Schmitz, Bonn, Germany
<td>Elektor custom IF, ADA831 2nd mxr, TUF-1,1st mxr preselector
<td>
<td>DReaM 1.1.6c
<td>5m wire
<td>DW Sines
<td>11830
<td>2005-02-05 (http://www.drmrx.org/forum/showthread.php?s=&postid=14947#post14947)
<tr><td>41.4 dB
<td>FritzWue DK6QI 52N 07E
<td>Flex-5000A
<td>
<td>DReaM 1.10.8cvs
<td>Inverted L- antenna,20m vertical
<td>BBC&DW
<td>9545
<td>2009-04-10 (http://www.drmrx.org/forum/showpost.php?p=54685&postcount=13)
<tr><td>42.0 dB Euro bonus:D
<td>FritzWue DK6QI 52N 07E
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.6.1cvs
<td>80m dipole up 20m
<td>DW
<td>13810
<td>2006-09-09 (http://www.drmrx.org/forum/showpost.php?p=30863&postcount=129)
<tr><td>41.2 dB
<td>Bernd DF9RB 150 km n. of Munich, Germany
<td>TS850 AGC inactive
<td>SA612 ceramic resonator
<td>DReaM 1.1.7c
<td>3-el ham Yagi, ALA1530, 30m wire
<td>Voice of Russia
<td>15780
<td>2005-01-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=14778#post14778)
<tr><td>40.6 dB
<td>DG9BFC, Barenburg, Germany
<td>IC-765 manual gain
<td>Sat-Schneider xtal
<td>Dream 1.6.1cvs
<td>170m delta loop
<td>DW Sines
<td>13810<td>2006-09-26 (http://www.drmrx.org/forum/showpost.php?p=31316&postcount=95)
<tr><td>40.3
<td>maxpower Oldenburg, Germany
<td>Pappradio dvlpd by Stephan
<td>
<td>DReaM 1.10.6cvs
<td>longwire
<td>DW Moosbrunn
<td>7310
<td>2008-07-04 (http://www.drmrx.org/forum/showpost.php?p=49244&postcount=110)
<tr><td>40.0 dB
<td>df8uo, Karlsruhe, Germany
<td>FT757GX
<td>Sat-Schneider xtal
<td>Dream 1.3c
<td>dipole
<td>VOR
<td>15780<td>2005-10-03 (http://www.drmrx.org/forum/showthread.php?s=&postid=21210#post21210)
<tr><td>39.1 dB
<td>Digger, CH-5023 Biberstein
<td>FRG7700 + Stabilock 4040 LO
<td>SO42P xtal
<td>Dream 1.6.1cvs
<td>16m LW + 1:1 un-un
<td>DW
<td>13810
<td>2006-09-23 (http://www.drmrx.org/forum/showpost.php?p=30890&postcount=93)
<tr><td>39.1 dB
<td>mitajohn Athens, Greece
<td>Sat-Schneider DRT1
<td>
<td>Dream 1.6.1 cvs
<td>Inverted "L" 9V/16H m
<td>MOI Kuwait
<td>13620
<td>2008-05-11 (http://www.drmrx.org/forum/showpost.php?p=48067&postcount=167)
<tr><td>37.9 dB
<td>simone, Bad Salzschlirf, Germany
<td>FRG100 AGC off
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>11830
<td>2005-02-08 (http://www.drmrx.org/forum/attachment.php?s=&postid=15035)
<tr><td>37.8 dB
<td>Francois, Petite Rosselle, Fr.
<td>ELAD FDM77 AGC SW + SLOW
<td>
<td>Dream 1.6.1cvs
<td>Twin Zepp
<td>DW
<td>13810
<td>2006-11-17 (http://www.drmrx.org/forum/showpost.php?p=33193&postcount=194)
<tr><td>37.6 dB
<td>hsseppo, Helsinki, Finland
<td>AD8099, AD9551, AD831, 21.4 IF
<td>AD831
<td>DReaM 1.2.5c
<td>5m wire
<td>VoR
<td>15780
<td>2005-06-30 (http://www.drmrx.org/forum/attachment.php?s=&postid=18509)
<tr><td>37.5 dB
<td>Han, Netherlands
<td>AOR AR 7030 unmodified
<td>Sat-Schneider
<td>DReaM 1.5cvs
<td>ALA 1530
<td>DW Sines
<td>17700
<td>2006-01-21 (http://www.drmrx.org/forum/attachment.php?attachmentid=17536&d=1138526798)
<tr><td>36.5 dB
<td>CT1ADT, Sines, Portugal
<td>TS-870 unmodified
<td>11,3 kHz out
<td>DRM 2.0.34
<td>8m vert or 24m dipole
<td>VOR
<td>15780
<td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
<tr><td>36.3 dB
<td>carknue, Frankfurt, Germany
<td>AOR-7030 AGC off
<td>Sat-Schneider xtal
<td>DRMSWR 2.0.34
<td>Wellbrook ALA1530P
<td>DW
<td>5980
<td>2005-10-14 (http://www.drmrx.org/forum/showthread.php?s=&postid=21541#post21541)
<tr><td>35.9 dB
<td>johnn, Scunthorpe, N.Lincs, UK
<td>DRT-1
<td>
<td>DReaM 1.5cvs
<td>AL1530 loop
<td>DW Sines
<td>17700
<td>2005-12-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=23725#post23725)
<tr><td>35.9 dB
<td>Funkerberg, Königs Wusterhausen, near Berlin
<td>Elektor
<td>
<td>Dream 1.6.1cvs
<td>10m dipole
<td>DW
<td>5810
<td>2006-03-04 (http://www.drmrx.org/forum/attachment.php?attachmentid=18960&d=1141639182)
<tr><td>35.6 dB
<td>arniek, Muenster, Germany
<td>FRG-100
<td>Sat-Schneider
<td>DReaM 1.1.1c
<td>homemade loop
<td>DW Sines
<td>5980
<td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
<tr><td>35.2 dB
<td>fibber - Salem, Oregon USA
<td>Yaesu FT-817, 10dB Radio Shack preamp, NCL MW Filter
<td>I5XWW 455k to 12k board
<td>Dream 1.6.1c
<td>80M Dipole
<td>RNW
<td>6130
<td>2008-02-07 (http://www.drmrx.org/forum/showpost.php?p=45683&postcount=99)
<tr><td>34.9 dB
<td>dn0758
<td>elektor
<td>
<td>DRMSWR 2.0.34
<td>Sony AN-1
<td>DW Sines
<td>17800
<td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
<tr><td>34.4 dB
<td>chemclouds, Richmond, Va, USA
<td>Icom IC-R75 AGC off
<td>
<td>DRMSWR 2.0.34
<td>30m inverted-L
<td>CBC Sackville
<td>9800
<td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
<tr><td>34.3 dB
<td>FritzWue DK6QI 52N 07E
<td>FT840
<td>Sat-Schneider
<td>DReaM 1.1.6c
<td>2x 40m LW
<td>DW-Sines
<td>17800
<td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
<tr><td>34.3 dB
<td>Kjell Holen LA6XJ Bergen, Norway
<td>Sat-Schneider DRT1
<td>
<td>DReaM 1.1.7c
<td>70 cm indoor loop
<td>Voice of Russia
<td>12060
<td>2005-01-15 e-mail
<tr><td>34.2 dB
<td>Werner DK8FT
<td>IC R71 AGC off
<td>Sat-Schneider xtal
<td>Dream 1.1.6
<td>4m wire
<td>DW-Sines
<td>17710
<td>2005-02-20 not posted
<tr><td>33.5 dB
<td>johnn, Scunthorpe, N.Lincs, UK
<td>AOR 7030
<td>
<td>DReaM 1.2.4
<td>AL1530 loop
<td>Radio Luxembourg
<td>7145
<td>2005-10-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=22124#post22124)
<tr><td>33.2 dB
<td>G3VRF, Warwickshire , UK
<td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
<td>12kHz DRM xtal ctld
<td>DReaM 1.1.6c
<td>35cm tuned loop in attic 11m a.g.
<td>DW Sines
<td>11830
<td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
<tr><td>33.2 dB
<td>simone
<td>Coding Tech DWT
<td>
<td>Dream 1.2.3cvs
<td>long wire
<td>Bouquet Flevo NL
<td>7240
<td>2005-07-24 (http://www.drmrx.org/forum/showthread.php?s=&postid=19030#post19030)
<tr><td>32.5 dB
<td>Bob, St Albans UK
<td>AR88D (60 yrs young!)
<td>Sat-Schneider LC
<td>Dream 1.2.4
<td>Wellbrook LA5030 indoor loop
<td>DW
<td>13790
<td>2005-05-22 (http://www.drmrx.org/forum/showthread.php?s=&postid=17414#post17414)</td></tr>
<tr><td>32.5 dB
<td>Tom VE3MEO Toronto, Canada
<td>Radio Shack DX-394A no AGC nor 2nd IF fltr
<td>LF-D6 filter/NE612 protoboard
<td>DReaM 1.1.1c
<td>G5RV
<td>CBC Sackville
<td>6140
<td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
<tr><td>32 dB
<td>carknue, Frankfurt, Germany
<td>Coding Tech DWT
<td>
<td>Dream 1.3.1cvs
<td>Degen DE31 Active Loop
<td>DW
<td>5980
<td>2005-10-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=21315#post21315)
<tr><td>31.2 dB
<td>DRM-OM, 25km SE Karlsruhe, Germany
<td>DRT-1
<td>
<td>Dream 1.6.1cvs
<td>Dressler ara100 active ant.
<td>Radio Luxembourg
<td>7295
<td>2006-04-25 (http://www.drmrx.org/forum/showpost.php?p=27082&postcount=91)
<tr><td>30.7 dB
<td>simone
<td>FRG8800
<td>Sat-Schneider
<td>DRMSWR 2.0.34
<td>whip
<td>DW Sines
<td>15435
<td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
<tr><td>30.4 dB
<td>TimoHannes, Petäjävesi, Finland
<td>elektor
<td>?
<td>DRMSWR 2.0.34
<td>active
<td>DW Sines
<td>17800
<td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
</table> [/B]

[dadalbinder]

Hallo,

some thoughts, experiences about the features of the list.

Wolfgang Hartmann, Nürnberg

[mvs sarma]

Hallo,

some thoughts, experiences about the features of the list.

Wolfgang Hartmann, Nürnberg
Thanks for such Nice paper with detailed observations, WolfgangHartmann !!

[dadalbinder]

Hallo,

I wrote some notes on the list.

Enclosed You see a diagram worked out by SoDiRa 0.74 on a basis of "3 frames".

Here You can clearly see, that the amplitudes in DRM-transmitting are changing very quickly. More movement as in comparison in a minute-based documentation.

Especially You are able to see, how very fast agc-regulation would destroy the original DRM-signal. On the other hand there is no need of too much agc.

The regulation is done by agc within the decoding programm.

It is very surprising how fast amplitudes change on the way from the transmitter to the receiver. Phase-changings, reflections, .....

There are very fast changings of amplitudes till to 20 dB differences.

Wolfgang Hartmann, Nürnberg

[simone]

Highest SNR's over 30 dB achieved with DRMRX/DReaM

updated: FritzWue, now achieving 42.5 dB using a Flex-5000A Rx
edit 08 Nov: FritzWue, now achieving 42.8 dB using a Flex-5000A Rx





<table align="LEFT" border="1"><tbody><tr><th>Max SNR
</th><th>By
</th><th>Receiver
</th><th>Converter
</th><th>App
</th><th>Antenna
</th><th>Service
</th><th>Freq(kHz)
</th><th>Date</th></tr><tr><td>51.4 dB
</td><td>hsseppo, Helsinki, Finland
</td><td>AD8099, AD9551, AD831, 21.4 IF
</td><td>AD831
</td><td>DReaM 1.2.5c
</td><td>Direct from Tx
</td><td>Dream Test
</td><td>10012
</td><td>2005-06-30 (http://www.drmrx.org/forum/showthread.php?s=&postid=18514#post18514)
</td></tr><tr><td>48.3 dB
</td><td>mitajohn Athens, Greece
</td><td>Sat-Schneider DRT1
</td><td>
</td><td>Dream
</td><td>Dream -t burnt CD played into SA602 up-mixer
</td><td>test
</td><td>1000
</td><td>2008-02-09 (http://www.drmrx.org/forum/showpost.php?p=45729&postcount=103)
</td></tr><tr><td>48 dB
</td><td>DRM-OM (Bernhard), 25km SE Karlsruhe Germany
</td><td>Sat-Schneider DRT1
</td><td>
</td><td>Fraunhofer IIS software radio V4.0.40
</td><td>Direct from Tx
</td><td>Test
</td><td>6000
</td><td>2006-04-24 German (http://privat.albicker.org/kurzwelle-drm/umbau-drt1.html),

English Translation (http://translate.google.com/translate?u=http%3A%2F%2Fprivat.albicker.org%2Fkur zwelle-drm%2Fumbau-drt1.html&langpair=d%3Cbr%20/%3E%0A%3Cbr%20/%3E%0Ae%7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools)
</td></tr><tr><td>45.1 dB
</td><td>Bernd DF9RB 150 km n. of Munich, Germany
</td><td>Sat-Schneider DRT1
</td><td>
</td><td>DReaM 1.3.1cvs
</td><td>3-el ham Yagi, ALA1530, 30m wire or EWE
</td><td>Voice of Russia
</td><td>15780
</td><td>2005-10-16 (http://www.drmrx.org/forum/showthread.php?s=&postid=21605#post21605)
</td></tr><tr><td>42.1 dB
</td><td>René Schmitz, Bonn, Germany
</td><td>Elektor custom IF, ADA831 2nd mxr, TUF-1,1st mxr preselector
</td><td>
</td><td>DReaM 1.1.6c
</td><td>5m wire
</td><td>DW Sines
</td><td>11830
</td><td>2005-02-05 (http://www.drmrx.org/forum/showthread.php?s=&postid=14947#post14947)
</td></tr><tr><td>42.8 dB
</td><td>FritzWue DK6QI 52N 07E
</td><td>Flex-5000A
</td><td>
</td><td>DReaM 1.10.8cvs
</td><td>Inverted L- antenna,20m vertical
</td><td>VoR
</td><td>7325
</td><td>2009-11-08 (http://www.drmrx.org/forum/showpost.php?p=58004&postcount=18)
</td></tr><tr><td>42.0 dB
</td><td>FritzWue DK6QI 52N 07E
</td><td>Sat-Schneider DRT1
</td><td>
</td><td>DReaM 1.6.1cvs
</td><td>80m dipole up 20m
</td><td>DW
</td><td>13810
</td><td>2006-09-09 (http://www.drmrx.org/forum/showpost.php?p=30863&postcount=129)
</td></tr><tr><td>41.2 dB
</td><td>Bernd DF9RB 150 km n. of Munich, Germany
</td><td>TS850 AGC inactive
</td><td>SA612 ceramic resonator
</td><td>DReaM 1.1.7c
</td><td>3-el ham Yagi, ALA1530, 30m wire
</td><td>Voice of Russia
</td><td>15780
</td><td>2005-01-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=14778#post14778)
</td></tr><tr><td>40.6 dB
</td><td>DG9BFC, Barenburg, Germany
</td><td>IC-765 manual gain
</td><td>Sat-Schneider xtal
</td><td>Dream 1.6.1cvs
</td><td>170m delta loop
</td><td>DW Sines
</td><td>13810</td><td>2006-09-26 (http://www.drmrx.org/forum/showpost.php?p=31316&postcount=95)
</td></tr><tr><td>40.3
</td><td>maxpower Oldenburg, Germany
</td><td>Pappradio dvlpd by Stephan
</td><td>
</td><td>DReaM 1.10.6cvs
</td><td>longwire
</td><td>DW Moosbrunn
</td><td>7310
</td><td>2008-07-04 (http://www.drmrx.org/forum/showpost.php?p=49244&postcount=110)
</td></tr><tr><td>40.0 dB
</td><td>df8uo, Karlsruhe, Germany
</td><td>FT757GX
</td><td>Sat-Schneider xtal
</td><td>Dream 1.3c
</td><td>dipole
</td><td>VOR
</td><td>15780</td><td>2005-10-03 (http://www.drmrx.org/forum/showthread.php?s=&postid=21210#post21210)
</td></tr><tr><td>39.1 dB
</td><td>Digger, CH-5023 Biberstein
</td><td>FRG7700 + Stabilock 4040 LO
</td><td>SO42P xtal
</td><td>Dream 1.6.1cvs
</td><td>16m LW + 1:1 un-un
</td><td>DW
</td><td>13810
</td><td>2006-09-23 (http://www.drmrx.org/forum/showpost.php?p=30890&postcount=93)
</td></tr><tr><td>39.1 dB
</td><td>mitajohn Athens, Greece
</td><td>Sat-Schneider DRT1
</td><td>
</td><td>Dream 1.6.1 cvs
</td><td>Inverted "L" 9V/16H m
</td><td>MOI Kuwait
</td><td>13620
</td><td>2008-05-11 (http://www.drmrx.org/forum/showpost.php?p=48067&postcount=167)
</td></tr><tr><td>37.9 dB
</td><td>simone, Bad Salzschlirf, Germany
</td><td>FRG100 AGC off
</td><td>Sat-Schneider
</td><td>DRMSWR 2.0.34
</td><td>whip
</td><td>DW Sines
</td><td>11830
</td><td>2005-02-08 (http://www.drmrx.org/forum/attachment.php?s=&postid=15035)
</td></tr><tr><td>37.8 dB
</td><td>Francois, Petite Rosselle, Fr.
</td><td>ELAD FDM77 AGC SW + SLOW
</td><td>
</td><td>Dream 1.6.1cvs
</td><td>Twin Zepp
</td><td>DW
</td><td>13810
</td><td>2006-11-17 (http://www.drmrx.org/forum/showpost.php?p=33193&postcount=194)
</td></tr><tr><td>37.6 dB
</td><td>hsseppo, Helsinki, Finland
</td><td>AD8099, AD9551, AD831, 21.4 IF
</td><td>AD831
</td><td>DReaM 1.2.5c
</td><td>5m wire
</td><td>VoR
</td><td>15780
</td><td>2005-06-30 (http://www.drmrx.org/forum/attachment.php?s=&postid=18509)
</td></tr><tr><td>37.5 dB
</td><td>Han, Netherlands
</td><td>AOR AR 7030 unmodified
</td><td>Sat-Schneider
</td><td>DReaM 1.5cvs
</td><td>ALA 1530
</td><td>DW Sines
</td><td>17700
</td><td>2006-01-21 (http://www.drmrx.org/forum/attachment.php?attachmentid=17536&d=1138526798)
</td></tr><tr><td>36.5 dB
</td><td>CT1ADT, Sines, Portugal
</td><td>TS-870 unmodified
</td><td>11,3 kHz out
</td><td>DRM 2.0.34
</td><td>8m vert or 24m dipole
</td><td>VOR
</td><td>15780
</td><td>2004-01-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=5210#post5210)
</td></tr><tr><td>36.3 dB
</td><td>carknue, Frankfurt, Germany
</td><td>AOR-7030 AGC off
</td><td>Sat-Schneider xtal
</td><td>DRMSWR 2.0.34
</td><td>Wellbrook ALA1530P
</td><td>DW
</td><td>5980
</td><td>2005-10-14 (http://www.drmrx.org/forum/showthread.php?s=&postid=21541#post21541)
</td></tr><tr><td>35.9 dB
</td><td>johnn, Scunthorpe, N.Lincs, UK
</td><td>DRT-1
</td><td>
</td><td>DReaM 1.5cvs
</td><td>AL1530 loop
</td><td>DW Sines
</td><td>17700
</td><td>2005-12-31 (http://www.drmrx.org/forum/showthread.php?s=&postid=23725#post23725)
</td></tr><tr><td>35.9 dB
</td><td>Funkerberg, Königs Wusterhausen, near Berlin
</td><td>Elektor
</td><td>
</td><td>Dream 1.6.1cvs
</td><td>10m dipole
</td><td>DW
</td><td>5810
</td><td>2006-03-04 (http://www.drmrx.org/forum/attachment.php?attachmentid=18960&d=1141639182)
</td></tr><tr><td>35.6 dB
</td><td>arniek, Muenster, Germany
</td><td>FRG-100
</td><td>Sat-Schneider
</td><td>DReaM 1.1.1c
</td><td>homemade loop
</td><td>DW Sines
</td><td>5980
</td><td>2004-10-08 (http://www.drmrx.org/forum/showthread.php?s=&postid=11206#post11206)
</td></tr><tr><td>35.2 dB
</td><td>fibber - Salem, Oregon USA
</td><td>Yaesu FT-817, 10dB Radio Shack preamp, NCL MW Filter
</td><td>I5XWW 455k to 12k board
</td><td>Dream 1.6.1c
</td><td>80M Dipole
</td><td>RNW
</td><td>6130
</td><td>2008-02-07 (http://www.drmrx.org/forum/showpost.php?p=45683&postcount=99)
</td></tr><tr><td>34.9 dB
</td><td>dn0758
</td><td>elektor
</td><td>
</td><td>DRMSWR 2.0.34
</td><td>Sony AN-1
</td><td>DW Sines
</td><td>17800
</td><td>2004-11-20 (http://www.drmrx.org/forum/attachment.php?s=&postid=12422)
</td></tr><tr><td>34.4 dB
</td><td>chemclouds, Richmond, Va, USA
</td><td>Icom IC-R75 AGC off
</td><td>
</td><td>DRMSWR 2.0.34
</td><td>30m inverted-L
</td><td>CBC Sackville
</td><td>9800
</td><td>2004-11-27 (http://www.drmrx.org/forum/attachment.php?s=&postid=12647)
</td></tr><tr><td>34.3 dB
</td><td>FritzWue DK6QI 52N 07E
</td><td>FT840
</td><td>Sat-Schneider
</td><td>DReaM 1.1.6c
</td><td>2x 40m LW
</td><td>DW-Sines
</td><td>17800
</td><td>2004-12-18 (http://www.drmrx.org/forum/attachment.php?s=&postid=13185)
</td></tr><tr><td>34.3 dB
</td><td>Kjell Holen LA6XJ Bergen, Norway
</td><td>Sat-Schneider DRT1
</td><td>
</td><td>DReaM 1.1.7c
</td><td>70 cm indoor loop
</td><td>Voice of Russia
</td><td>12060
</td><td>2005-01-15 e-mail
</td></tr><tr><td>34.2 dB
</td><td>Werner DK8FT
</td><td>IC R71 AGC off
</td><td>Sat-Schneider xtal
</td><td>Dream 1.1.6
</td><td>4m wire
</td><td>DW-Sines
</td><td>17710
</td><td>2005-02-20 not posted
</td></tr><tr><td>33.5 dB
</td><td>johnn, Scunthorpe, N.Lincs, UK
</td><td>AOR 7030
</td><td>
</td><td>DReaM 1.2.4
</td><td>AL1530 loop
</td><td>Radio Luxembourg
</td><td>7145
</td><td>2005-10-29 (http://www.drmrx.org/forum/showthread.php?s=&postid=22124#post22124)
</td></tr><tr><td>33.2 dB
</td><td>G3VRF, Warwickshire , UK
</td><td>AD9852 DDS, AD831 Mixer, 2x AD603 IF
</td><td>12kHz DRM xtal ctld
</td><td>DReaM 1.1.6c
</td><td>35cm tuned loop in attic 11m a.g.
</td><td>DW Sines
</td><td>11830
</td><td>2004-11-24 (http://www.drmrx.org/forum/attachment.php?s=&postid=12541)
</td></tr><tr><td>33.2 dB
</td><td>simone
</td><td>Coding Tech DWT
</td><td>
</td><td>Dream 1.2.3cvs
</td><td>long wire
</td><td>Bouquet Flevo NL
</td><td>7240
</td><td>2005-07-24 (http://www.drmrx.org/forum/showthread.php?s=&postid=19030#post19030)
</td></tr><tr><td>32.5 dB
</td><td>Bob, St Albans UK
</td><td>AR88D (60 yrs young!)
</td><td>Sat-Schneider LC
</td><td>Dream 1.2.4
</td><td>Wellbrook LA5030 indoor loop
</td><td>DW
</td><td>13790
</td><td>2005-05-22 (http://www.drmrx.org/forum/showthread.php?s=&postid=17414#post17414)</td></tr> <tr><td>32.5 dB
</td><td>Tom VE3MEO Toronto, Canada
</td><td>Radio Shack DX-394A no AGC nor 2nd IF fltr
</td><td>LF-D6 filter/NE612 protoboard
</td><td>DReaM 1.1.1c
</td><td>G5RV
</td><td>CBC Sackville
</td><td>6140
</td><td>2004-10-19 (http://www.drmrx.org/forum/showthread.php?s=&postid=11441#post11441)
</td></tr><tr><td>32 dB
</td><td>carknue, Frankfurt, Germany
</td><td>Coding Tech DWT
</td><td>
</td><td>Dream 1.3.1cvs
</td><td>Degen DE31 Active Loop
</td><td>DW
</td><td>5980
</td><td>2005-10-07 (http://www.drmrx.org/forum/showthread.php?s=&postid=21315#post21315)
</td></tr><tr><td>31.2 dB
</td><td>DRM-OM, 25km SE Karlsruhe, Germany
</td><td>DRT-1
</td><td>
</td><td>Dream 1.6.1cvs
</td><td>Dressler ara100 active ant.
</td><td>Radio Luxembourg
</td><td>7295
</td><td>2006-04-25 (http://www.drmrx.org/forum/showpost.php?p=27082&postcount=91)
</td></tr><tr><td>30.7 dB
</td><td>simone
</td><td>FRG8800
</td><td>Sat-Schneider
</td><td>DRMSWR 2.0.34
</td><td>whip
</td><td>DW Sines
</td><td>15435
</td><td>2004-10-10 (http://www.drmrx.org/forum/attachment.php?s=&postid=11276)
</td></tr><tr><td>30.4 dB
</td><td>TimoHannes, Petäjävesi, Finland
</td><td>elektor
</td><td>?
</td><td>DRMSWR 2.0.34
</td><td>active
</td><td>DW Sines
</td><td>17800
</td><td>2004-11-14 (http://www.drmrx.org/forum/attachment.php?s=&postid=12257)
</td></tr></tbody></table> [/b]