Many people will have heard about the DRM (Digital Rights Management), which was introduced recently on behalf of the record industry in their own 'war on terrorism', which for them is due to the fact that people are not willing to pay excessive prices for CD's and DVD's and therefore distribute home-recorded copies among friends and through p2p (peer-to-peer) networks.
This page is NOT dedicated to this agressive type of DRM, but to an older, though still not as widely known, type of DRM, Digital Radio Mondiale, which consists in a digital transmission mode for radio signals. For more -and more technical- background information, I suggest you visit the website of the DRM Consortium.
I would simply like to give you some sound samples of broadcasts of DMR signals, as I receive them at my home in a little village north of Amsterdam in the Netherlands.
DRM will surprise anybody who has never heard anything else than AM signals on long, medium and short wave, too often plagued by fading, interference by stations on the same or an adjacent frequency and low audio quality (the audio spectrum of AM signals is generally abruptly cut off below 5 kHz)
Not so for DRM, which sounds much like FM (VHF-broadcasts) as we know from frequencies between 87.5 and 108 MHz. Just as on FM, DRM also can be broadcast in stereo (listen e.g. to the recording from German WDR 2)and there is no trace of fading or interference from other stations. Moreover the signals can in certain cases reach the other side of the world in a few 'hops'.
There is however one drawback: either you hear the DRM signal in good quality or you don't hear it at all. And if the radiosignal suffers from fading or from varying interference you can hear it appearing and desappearing (as in the recording from RFI, France), which is not pleasant to listen to.
Another problem does not so much relate to DRM-reception, but rather to reception of non-DRM transmissions, because at present the DRM-tests are being carried out in the normal broadcasting bands, where they cause more interference than normal AM-stations.
Anyway, below you will find a couple of soundbits from DRM-broadcasts:
|Bitexpress Berlin (15896 khz, July 26, 07:00 UTC)|
|Deutsche Welle (13810 khz, July 26, 10:00 UTC, relayed from Sines/Portugal)|
|WDR [Westdeutscher Rundfunk] 2 (1593 khz, July 26, 00:00 UTC)|
|RFI [Radio France International] (3965 khz, July 27, 01:00 UTC)|
|Radio Kuwait (13620 khz, July 26, 12:00 UTC)|
|Radio Luxembourg [English programmes] (7295 khz, July 26, 09:20 UTC) (broadcast from the UK)|
|RTL [French programmes] (5990 khz, July 16, 08:00 UTC)|
|RTL [German programmes] (6095 khz, July 17, 09:00 UTC)|
|Radio Netherlands [Radio Nederland Wereldomroep] (7240 khz, July 26, 13:00 UTC)|
|Voice of Russia (12060 khz, July 26, 09:00 UTC)|
|BBC World Service (1296 khz, July 16, 10:00 UTC)|