HF Digital modes

[vkcpolice]

Hi ive been reading around the net about people using digital modulation on the hf bands. Any one know what this modulation is im guessing its not p25 and what scanner could monitor these transmissions

[Comint]

Hi ive been reading around the net about people using digital modulation on the hf bands. Any one know what this modulation is im guessing its not p25 and what scanner could monitor these transmissions

Digital Radio Mondiale (DRM) - Mondiale supposedly means 'Worldwide' in French.

I don't know of any scanner that will monitor the transmissions.

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Comint

[chanjyj]

Hi ive been reading around the net about people using digital modulation on the hf bands. Any one know what this modulation is im guessing its not p25 and what scanner could monitor these transmissions

Which people? There are so many digital modes for HF.

[Vkfour]

I have been meaning to answer this for a few days, but Mr Chanjyj beat me to it. As he says, there are heaps of HF digital modes, some carrying voice and music and others carrying data involving text, pictures, fax and the like. Can you hear it on your scanner? If your scanner covers from around 3MHz to 30 MHz and provided your scanner has SSB, and provided you are prepared to put up a decent antenna, and My Chanjy will be able to tell you the difficulties involved there if you have restricted space, then you should be able to hear it. Can you monitor it? It will just be noise, however, if you know what sort of signals are likely to be where, how to identify them, and you have a computer and the software to resolve them, then you probably can. Interestingly, with some digital modes, YOU don't need to be able to hear the actual signal. The computer soundcard can hear it electronically and show you where the signal is, within a very narrow range, on its screen. Actually, it is quite fascinating to "hear" some of these digital modes without actually "hearing" them.

[chanjyj]

If you can narrow down the frequency it will be trivial to tell you how long an antenna you need... in metres. Though I think we can "cheat" and shorten it some as you are just receiving, not transmitting.

[vkcpolice]

I had a 17ft 27mhz antenna on my roof at my old house and used to hear almost everything on every hf band since becomming homeless im stuck to my little alinco djx10 and recieving hf on a handheld is horrible

[melbourneradio]

digging up an old thread !! while fiddling around the other day ,, I noticed conditions were open around 10 meters , thought just for laughs I would see what was happening across 11 meters , and panned down and I noted several data modes above the 40 chan allocation , sounded like heli or sstv ,, I could only rx so didn't look into it any further ,,, but recalled these comments so I thought I would add to it !!

[erikn]

digging up an old thread !! while fiddling around the other day ,, I noticed conditions were open around 10 meters , thought just for laughs I would see what was happening across 11 meters , and panned down and I noted several data modes above the 40 chan allocation , sounded like heli or sstv ,, I could only rx so didn't look into it any further ,,, but recalled these comments so I thought I would add to it !!

I saw an episode of Amateur Logic where they used D-STAR to talk on HF - but that was well below 11m.

If you'd have had a SSTV program on your computer and patched the speaker output of your radio into the mic input on your computer and rigged it so the mic input was default recording device you might have been able to find out whether it was SSTV or not. I also went to a SOTA weekend a couple months ago where a fellow ham showed off analogue and digital SSTV modes - digital SSTV iirc had error correction whereas analogue did not.