DRM Radio

Foggy43

I'm just curious if anyone has tuned in to DRM radio.
I have just done some surfing on the subject and it appears to use Short Wave only even though it can use Medium and Long Wave. There just seems to be 2 portable receivers on the market but there are PC cards available.

I did read somewhere that DRM will happen in the UK! I will try and find that website again.

DMC

BBC World Service is broadcast on DRM, but I think the BBC are still experimenting with it.

DMC

More news...

DRM tests underway

http://theairwaves.thebigboards.net/index.php?option=com_content&task=view&id=2298&Itemid=2

Written by Robert Piercy
Tuesday, 08 November 2005

A six week test of Digital Radio Mondiale (DRM) are underway in the London area.
The stations taking part in the tests are BBC World Service, Virgin Radio, TalkSPORT and Kiss 100. The trial is designed to see if the broadcast quality, said to be just less than FM, are viable for commercial broadcasting. There are currently no DRM radios available to buy but combined DAB and DRM sets are expected to hit the shops by Christmas.

DRM is an alternative digital technology to DAB and one transmitter can reach a much larger range than DAB. You could liken DAB to FM and DRM to AM. The broadcast quality is said to be slightly lower than current FM signals.

DRM is being pouted as a lower cost option than DAB. This could assist smaller stations which may not be able to afford to broadcast on DAB.

Antenna

Molly Dawson wrote:

I'm just curious if anyone has tuned in to DRM radio.
I have just done some surfing on the subject and it appears to use Short Wave only even though it can use Medium and Long Wave.

There are a few DRM test broadcasts to be found on MW and LW.
You will "hear" DRM experimental broadcasts transmitted on 1440kHz from RTL Luxembourg every night for a few hours.
Tuning in on an AM radio you will just hear a loud white noise with a churning type effect

DMC

Ahhh, fabulous 208 lives on...

lawhec

There are a couple of commercial DRM receivers out there, though they don't really have any publicity beyond the anorack community.

RTL's tests are on 1440 now during the afternoons and after midnight. Deutschlandradio Berlin now has given over its 177kHz transmitter to permenant DRM.

Most of the UK DRM tests are very low powered - the London test below is on a frequency just below the CB Band.

Mossy Monk

what kind of reception range would be on this sort of broadcast?

lawhec

Mossy Monk wrote:

what kind of reception range would be on this sort of broadcast?

Mossy, I understan that the London test is 400W ERP using a yagi aerial at Crystal Palace.

Mossy Monk

in English that means

DMC

Small beer. Consider FM Radio from Mt Leinster transmits at 400kW.

dojo

I converted my sony SW radio to DRM by taping the IF from the circuit board and passing if through an IF converter I bought online for 50 euros, the output from the converter is sent to the line in of a soundcard and free software decodes the signal.

The results were impressive, near FM stereo quality audio + text and graphics. The signal would breakup every now a then, but I was only using the telescopic antenna.

The sony radio still works perfectly, apart from the little used line out socket, which is now IF out, overall it was a simple project and keeping the converter outside of the sony allows it to be used on other SW radio's, so far the only other radio tested was a Jwin and that had good results too.

If anyone wants pictures or diagrams let me know

Dojo

DMC

Welcome along, I and all the posters here would love to have a look at those.

You can attach pictures to your posts, or boards offers 5MB of webspace for anything, for free. http://members.boards.ie/

byrnefm

I'd be interested in knowing how you constructed it, too! Did you have to disassemble your radio? (I've a Sangean ATS-909 but it has a line-out socket, too, which I don't presently use).

dojo

I'll put together some documentation on the project, with pictures and schematics (give me a few days), the whole project was fairly simple and took a few hours, documenting it could take as long.

DMC

Looking forward to it. No rush.

dojo

Hi, attached is 3 pictures of my DRM project, the quality is poor so I'll take them again when I get another camera.





The circuit board on the back of the sony.jpg has an a and b marking. A points to the IF tap point, a sheilded cable is simply soldered on to the leg of an IF filter (took about 10 mins to find through trial and error). The other end marked B goes to the positive of the line out socket. I scrached a track on the board to stop line out AF(audio frequency) mixing with the IF (intermediate frequency).



The converter is simple, a 9v PP3 powers the down-converter but this could be 6-12vdc (it think). The down converter was purchased from Germany for about 40 euros (I'll dig out the address + wiring diagram for anyone that's interested).The down converter is about the size of a 1 euro coin an could easily fit inside most receivers.

Next I'll create some screen shots of the DRM software in action and some samples of the quality of sound.

Donal

DMC

Well done. Facinating!