Max SNR as Indicator of RX Performance?

[DRM-OM]

My first try on real world signals

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]

Re: Max SNR table - the ascent to 40dB AND BEYOND!

Here are the latest changes to the table.

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]

Record SNR

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)

[VE3MEO]

Re: Max SNR table - the ascent to 40dB AND BEYOND

Here are the latest changes to the table.

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]

Re: Max SNR table - the ascent to 40dB AND BEYOND

Here are the latest changes to the table.

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]

Still updating the SNR list?

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!

[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.

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!
I never saw anything even close to 30dB with my older model.