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rlogue
01-04-2007, 10:53
I have a Digital World Traveller DRM radio which works OK for strong SW signals but so far I've had no luck with the RTE tests on 252. I've used the retractable wire antenna that comes with the radio but that doesn't even give me BBC Radio 4 on 198 kHz here in London, let alone the standard transmissions that go out on 252. I have a small Roberts Sports Radio that can pull in standard transmissions on 252 with acceptable results but the Digital World Traveller can only pull in static and mush on that frequency!

I constructed a simple antenna with one of my children's slinky springs. This gives better results on SW but makes little or no difference on MW or LW. So would I be better off with a frame loop antenna or a ferrite rod antenna?

richard
02-04-2007, 13:10
There is some info about this topic on a previous thread:-

http://www.drmrx.org/forum/showthread.php?t=698

It may be easiest to salvage a ferrite rod from an old radio with the long wave coil already wound. Connect this coil in parallel with a tuning capacitor. Connect one side of the tuned circuit to the antenna input and the other to receiver ground. Tune the capacitor until you get an increase in signal.

I assume the antenna input on the DWT is high impedance. If not an FET buffer amplifier between the tuned antenna circuit and receiver input may be necessary. This also has an advantage in that you can connect the ferrite rod arrangement to the receiver using a length of shielded cable, allowing it to be moved away from the PC.

Richard

gccradioscience
06-03-2010, 05:12
I would recommend a loop antenna or magnetically shielded active antenna for long wave for DRM. When I get this communications receiver in my house, I will try to see if I can receive the station on 243 kHz via ground wave via trans-atlantic DX. If this happens, which it will happen one day, I will set a record out on the forum. I may use a huge loop antenna to pull it in as best as I can. There is another type of active antenna I would recommend too, but its available in the USA, it's called a signal magnet antenna kit with a pre amp, but you have to be good in soldering MOSFET's to get it working. Wind about 200 to 300 turns and you got your self a good well performing ferrite loop antenna for long wave. One more thing there is various loops and active antennas out there. Main reason why I recommend magnetically shielded, it's because man made electrical noise and 0's and 1's do not get along too well causing reading errors and rebuffering problems.

gccradioscience
06-03-2010, 05:34
I have a Digital World Traveller DRM radio which works OK for strong SW signals but so far I've had no luck with the RTE tests on 252. I've used the retractable wire antenna that comes with the radio but that doesn't even give me BBC Radio 4 on 198 kHz here in London, let alone the standard transmissions that go out on 252. I have a small Roberts Sports Radio that can pull in standard transmissions on 252 with acceptable results but the Digital World Traveller can only pull in static and mush on that frequency!

I constructed a simple antenna with one of my children's slinky springs. This gives better results on SW but makes little or no difference on MW or LW. So would I be better off with a frame loop antenna or a ferrite rod antenna?

I didn't know that RTE is going DRM, oh boy. I need to get another radio with long wave, unless I modify my DX-392 with an IF output. I am going to have to get my DX-392 modifed for LW.

Siber
10-03-2010, 05:35
I have made a good LW loop antenna using of an alarm cable with four wires D= 0,4 mm inside. It is necessary to make six pieces of the cable , each = 4.2 m. In each piece the section of four turns is formed . Then sections incorporate consistently, forming L1- 20 turns and L2 - 4 turns. L3 is 25th turn of the antenna contour.
L3 is carried out by a separate wire. For L3 it is better to use a multicore wire, it also used as a cable to the receiver.
All 6 pieces of the cable and L3 wire incorporate in one loop by tape.
I use a variable capacity condenser from a portable receiver, all its 4 sections incorporate in parallel.
This antenna has two LW subBands 150-200 and 200-280 kHz that switched by SA1

For giving to the loop the form of a square, it is possible to use a cable channel 12x12 mm. In such packing it will be folding.See on the pic.

Telspace
10-03-2010, 16:49
First, the DWT receiver never gave me satisfaction. Very disapointed. Mine was changed twice free of charge by the manufacter, and still...

I have bought this : http://www.amantesdoradio.com.br/loja/rgp3/index.htm and tested in Belgium on longwaves. Imrproves the reception. I have build also a magnetic loop (4m x 4m). Check this : http://www.youtube.com/watch?v=PBYawoWT5pY and so far, nothing beat this.
Another link : http://www.frontiernet.net/~jadale/loop.htm

KD7YUF
22-04-2010, 08:32
These antennas would be useful for Americans too for either transPacific or transAtlantic DX or for those who listen for LW beacons. The best luck I have had is with a good old fashioned Beverage antenna but those are quite big and their size is prohibitive for those with small space to deal with unfortunately. Maybe someday someone will report trans Atlantic LW DRM reception from the US side since I know it can be done on shortwave from experience as I got the RCI transmissions from Sackville on 9.800 MHz on a Elad FDM77 SDR which was controllable through the internet and is sadly now defunct.