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carknue
13-06-2004, 10:09
Hi,

just want to start here a new thread, because hanyong has asked about our antennas in the reception results forum.

Perhaps all of us can post here their antennas for DRM, maybe with a picture.

I use the Wellbrook ALA 1530P magnetic loop. It fits perfectly on my balcony. I made bad results before with a 4m wire, because of too much noise.

hanyong
13-06-2004, 13:50
thank Carknue very much!
because I am a broadcast worker, we want to popularize DRM broadcast, so we want to imitate common recieve condition(no extend antenna or short soft wire),can you help me? please post logfile and result!
thank you!

df9rb
19-06-2004, 09:14
Hello,

here my antennas I can us for shortwave reception and comparision of SNRs.
Loop = Wellbrook ALA 1530, 8 m above ground
Wire = 30 m Longwire with 9:1 transformer, 8 m above ground
Yagi = 3 ele Yagi for Amateurradio, 15 m up
My RX = TS850 from Kenwood, mixer 455 kHz to 12 kHz
The interruption in the file 6095_Wire results from the
Bit Rate Change.

df9rb
19-06-2004, 09:14
6095_Wire

df9rb
19-06-2004, 09:19
6095 Yagi

df9rb
19-06-2004, 09:21
21675 Loop (DW from Trinconmale)

df9rb
19-06-2004, 09:21
21675 Wire

df9rb
19-06-2004, 09:23
21675 Yagi

Per
19-06-2004, 12:03
Hi,

I use a wideband discone antenna, that covers up to 1500 MHz. One advantage with this kind of antenna is the shielded cable (coax) that reduces interference from the computer. Also, it does not provide a too strong signal, hence the Rx (PCR-1000) is not overloaded.

73's Per

df9rb
30-08-2005, 12:41
Hi,

an other antenna test:

2nd graph is always a 40 m dipole (horizontal), 1st graph, first 1o minutes EWE (vertical), next 10 minutes Loop, next 10 minutes 30 m wire, at the end dipole and EWE connected together (not matched, phased).

Bernd, DF9RB

df9rb
27-03-2006, 14:28
Hi all,

after spring started also here in north east Bavaria I decided to substitute the old rusty pole carrying the ALA1530 and a 70 cm amateur yagi. The ALA1530 is now 10 m above ground (2 m higher than before). The first impression is that the nulling depth is now more than 30 dB on ground wave signals which is approx. 10 dB better than before. I also added two small DVB-T-antennas. I live out of the target area for this DVB-T transmitter even for roof antennas but the signal is stable with no observable video or audio drop outs. Before cable- and now satellite-TV I received the analog signal on the same channel (CH 6) on VHF with an 11 element antenna. The signal at this time was not noise free. Now I can receive 4 stations with excellent quality with a much smaller antenna and lower TX-power (25 kW instead 100 kW). On UHF 7 more stations are receiveable which was impossible before in analog times from this TX-site. I would call this a real improvment of DVB!!!! :) The lowest antenna is for AFN in analog.

Bernd, DF9RB

FritzWue
27-03-2006, 19:54
5/8L for 2 meter band as simple rod antenna prolonged with a wire to the preamplifier (BF245+BF199) inside the car:
(Revival of a very old thread, my post no.1000) :rolleyes:

richard
03-10-2006, 10:18
This antenna is effectively two coils in parallel on a type 61 ferrite. Both sets of turns are equal in number but are rapped around the rod in opposite directions. I believe this construction enables a higher Q, compared to that achievable using only one coil. I have not yet measured the inductance but I have used 16 turns of copper wire in total on the rod. The tuning capacitor is a cheap one salvaged from a radio, this must be around 130pF.

I use this antenna from 5.5-18MHz, although this range could no doubt be extended by using a higher value variable capacitance or switching inductances. The selectivity is very sharp and the tuning has to be adjusted, even moving between stations within the same band. You could shield the antenna for maximum E-field rejection. Directivity is still very good even without this though.

Richard

stegewicht
29-10-2006, 11:29
I use a ferrite rod with two coils (SW and MW) and an adjustable capacitor from an old receiver (radio).
So I have two ranges, from about 400kHz to 1600 kHz and from about 2000kHz to 10000kHz. This signal goes to a single amplifier with a FET (see the attached file) and then to the receiver-input.
In my oppinion I get the best results with this solution. For the higher frequencies I only use a long-wire antenna with a 9:1 balun.

df9rb
09-04-2007, 07:27
Hi,

this morning there was a very impressive difference between both antennas.
RTL on 1440 was below 20 µV with the EWE, with the ALA 1530 the s-meter showed approx. the same fieldstrength but the signal to noise ratio between the two antennas was amazing. See the attachment - the lower picture is the EWE.

Bernd, DF9RB

richard
29-08-2007, 11:52
Attaching details of a broadband ferrite antenna I made for use with my portable shortwave receiver. The antenna requires no tuning and consists of a small coil (now 12 turns of copper wire) wound on a 125 permeability ferrite rod. The signal is amplified by a simple RF transistor amplifier and fed to the radio via a short shielded cable.

The antenna sensitivity appears to be good (like the whip) and the response is directional. With the antenna shielded the receiver noise level does not appear to increase when using mains power. It would make a good antenna for a portable radio, no need to extend telescopic whip. I need to experiment to optimise the antenna to cover the whole of the shortwave band. In theory I could just add more turns of wire to increase signal pick up but then this decreases the resonance frequency of the antenna and it resonates at HF. Wonder if there is anyway to model this?

Richard

richard
16-09-2007, 17:23
Managed to make a comparison of DRM reception on DW 13.810MHz, using both the ferrite rod antenna and whip antenna with my radio (Degen 1102). The IF from the radio was converted using a Sat Schneider converter and decoding was done using a Toshiba laptop running from a noisy switched mode power supply. The antennas were located about 3 meters from the PC.

Predictably there were bad reception results when using the whip antenna, in fact the noise level caused by the switched mode power meant that decoding was totally impossible. Results with the ferrite rod were a lot better, with the SNR going from nothing to 20dB and the signal was stable! I even think the SNR could have been better with a more expensive receiver.

So even using a simple shielded ferrite rod like this big improvements in DRM reception are possible, especially went the decoding is done using equipment running from a noisy power supply.

Richard

mvs sarma
16-09-2007, 19:06
Managed to make a comparison of DRM reception on DW 13.810MHz, using both the ferrite rod antenna and whip antenna with my radio (Degen 1102). The IF from the radio was converted using a Sat Schneider converter and decoding was done using a Toshiba laptop running from a noisy switched mode power supply. The antennas were located about 3 meters from the PC.

Predictably there were bad reception results when using the whip antenna, in fact the noise level caused by the switched mode power meant that decoding was totally impossible. Results with the ferrite rod were a lot better, with the SNR going from nothing to 20dB and the signal was stable! I even think the SNR could have been better with a more expensive receiver.

So even using a simple shielded ferrite rod like this big improvements in DRM reception are possible, especially went the decoding is done using equipment running from a noisy power supply.

Richard
Hey Richard, Very encouraging info really. Coming to the radio used, I wonder why such or near approximate performance is not reported by any user of DE1103. the comments on one forum is that the DE1103 Mod for DRM did not serve the purpose. due to high noise figure as compared to SONY.

richard
16-09-2007, 19:45
Hello Sarma, I am no expert on this but maybe the DE1103 uses a less stable oscillator than the DE1102. If you have a DE1103 I would personally give the mod a try anyway, it will not cost a lot. Just put a socket on the receiver to get the IF(455KHz) output. You can then use external hardware to down convert the IF.

In the worst case if the modification doesn't work well, you should still have a working analogue receiver and can easily reuse the down converter in a future mod. Another advantage of using an external down converter is that it will not drain the receiver's batteries.

Richard

mvs sarma
17-09-2007, 10:44
Hello Sarma, I am no expert on this but maybe the DE1103 uses a less stable oscillator than the DE1102. If you have a DE1103 I would personally give the mod a try anyway, it will not cost a lot. Just put a socket on the receiver to get the IF(455KHz) output. You can then use external hardware to down convert the IF.

In the worst case if the modification doesn't work well, you should still have a working analogue receiver and can easily reuse the down converter in a future mod. Another advantage of using an external down converter is that it will not drain the receiver's batteries.

Richard
Hi Richard, one of my friends has one DE1103. the schematic is available . the iF appears to be 450KHz. the SNR is bad
this type mod was tried on it. but didn't perform well. mean time the Rx crashed and is on surgery table. after it is out and alive , we have to amke another attempt. It is also aPLL based animal. perhaps the nise level is more. thanks for the suggestion.

Regards
Sarma

andimik
27-09-2007, 11:38
It makes no sence to try to modify the DE1103 for DRM. You will hardly resp. never get audio.

http://www.knallfunke.de/drm/mod/mod-1103.htm (German only, but please see screenshots ...)

It's only useful to test, if a DRM signal could principially be received (switch to SSB and tune in 3 kHz higher, Flip Audio spectrum in DReaM) without modification.

mvs sarma
28-09-2007, 16:58
Thanks to Andimik for his comments. I could read the mod info on the said site, thanks to Yahoo translation.


Perhaps bandwidth needs to be increased or go for another Rx.

Thanks again

Regards
Sarma

mvs sarma
12-12-2007, 19:01
FYI, I found this link about DE1103 modification (in italian)

http://www.fmdx.altervista.org/articles.php?lng=it&pg=349

result is not good, yet there is some suggestion to try
Hai Mauri,
Thanks for the info. This is second of its kind. A mod for DE1103. this converter PCB I,shown in the referred site, came across E-bay, sometime back. if we use 443KHz ceramic we can convert to 12KHz. However, the bandwidth of the filters used and the SNR after conversion do not appear to be in tune. Finally, we may get the Station id but many times not the Audio. In fact I was trying for this mod in favor of one of my friends who happens to be a SWL.

Thanks again for the enormous interest taken. I am really late to see your post as didn't sign-in in the recent days.

mvs sarma
20-02-2008, 05:10
Thanks for the enquiry. Last week All India Radio has transmitted signals on 15050 KHz( please see the AIR Khampur HPT in reception results). But it is not coming as of now. this signal was traced at NewZeland and in parts of Europe.

The Indian Government has some plans as announced some time last year. We are also anxiously waiting for introduction. Initially the Receivers are bound to be costly.

KB0VE
25-02-2008, 01:29
My former QTH, (Ballwin, MO – a burb just west of St. Louis, MO) had lots of rules restricting outside antennas. Although behemoth cell phone towers sprang up everywhere like Midwest mushrooms, neighborhoods took great exception to rooftop antennas. With limited space inside my attic, I installed a discone antenna for its small size, wide response and ability to transmit on 6M, 2M and 70cm. I used this antenna to feed DRM to my WinRadio when not switched to my VHF amateur transceiver.

I am retired now and relocated to a rural area (Hawk Point, MO – a small town 55 mi NW of my former QTH) with no rules restricting outside antennas. The house had a flat panel antenna installed on the garage roof to connect broadband internet access before DSL was available locally. The cable between the antenna and shark fin Wi-Fi modem was hermetically sealed Times Microwave (LMR-400) type cable terminated with N connectors. This is good stuff. This cable is low loss well into the gigahertz range and practically no loss to HF. My new QTH had a built in interface for my discone and WinRadio. The attached photo shows me installing the discone where the flat panel used to be at ~ 10m. I made a short patch cable to interface the male N connector terminating the existing cable with the discone’s SO-239 type antenna connection. This was easier to fabricate at ground level, rather then replace the male type-N with a PL-259 at roof level. I’m not comfortable at roof level as evidenced by the rented personnel lift supporting me in the photo.

Although the discone specs list scanner use from 25 – 1300 MHz, the antenna is usable well below HF down to MF. My DRM reception log reports posted on the forum today (080224 local) for 7370, 9800 and 15315 kHz are all well below 25 MHz with solid copy using the discone. During this month’s Ducie Island DXpedition, I enjoyed Q5 copy of VP6DX on 1802 kHz CW using the discone. Although clearly not resonant to the lower bands, the antenna appears very quiet and delivers good SNR for DRM reception as evidenced from my referenced logs.;)

FritzWue
04-03-2008, 11:40
Trying different combinations of wires often gives very different results, see the difference for HCJB between a single inverted L and two inverted Ls fed as diploe with a balun. For RNZI the difference is similar but then the better result is with the single inverted L to the northeast.

KD7YUF
10-11-2009, 11:30
I might be better off in terms of antenna systems and in my case currently for analog reception (future DRM antennas) I am using a system of two antennas hooked up to my Icom R75 communications receiver. The antennas are a EWE aimed at Japan and the Korean peninsula and also a 1,275 foot unterminated beverage which I use mostly for the AM broadcast band but it has decent performance up to about 10 MHz where I end up with diminishing returns because of an elevated noise floor. There is also a third antenna in the system which is down now as I still need to get some RG-213 coax to hook it up with and that is a Cushcraft R7 vertical for amateur radio which also has great performance as a general coverage receive antenna.