1.75 mhz - 30 mhz DRM reciever to computer?

[SirDuke]

I was told you can use a computer to decode am shortwave digital signals just by plugging into the shortwave reciever earphone jack to the computer's soundcard line-in jack for CW SSB weather maps & info, Ship to shore, RTTY & other digital broadcasts. I tried to do this it don't work. Do I need a special program to make it work? I need info on how to do this, since I have 2 shortwave conitnuous recievers without a darn BFO in them to so the same thing with a reciever on only SSB & CW tho.

 

[ka3jjz]

There's your first problem. For most digital sigs (we'll get to DRM in a moment) you need a BFO - without it, you won't decode much of anything. Digital sigs are not really 'AM' - that's a bit of marketing hoopla.

As for DRM - there's really not that much beamed our way. And it is VERY sensitive to drop outs and noise. To decode that you need either a receiver which is already set up for it, or modify one. The modification is very similar in principle to what you would do for tapping a scanner for trunk decoding support.

Here are 2 articles on the subject from our wiki

HF Digital Decoding - The RadioReference Wiki

DRM

best regards..Mike

 

[SirDuke]

Digital from shortwave Radio to computer for decoding

Hi Mike Thank You for the reply & the information I found something I manage to get on my computer & don't know who or where it came from but it is called CwGet that supposially is suppose to work by just using it while the radio Earphone jack is connected to the computer's sound card Line Input Jack. I tried it it don't seem to work good at all with CW AKA Morse Code & works somewhat better for SSB but still quite garbled as far as other digital signals it doesn't seem to do anything at all for them AKA NO NOAA Weather Maps all all or anything else to do with RTTY reception? Can you get me more info about this particular prg & exactly what it shouldn't & shouldn't do for me? Thank You Eric

 

[ka3jjz]

You didn't say what radio(s) you are working with, but without a beat freq oscillator (or BFO) no program is going to work very well. Take a look at this page for a basic description of modulation and what a BFO does;

Radio Modes and Modulation RTTY

CwGet is set up to only decode morse code, or CW (for continuous wave), nothing else. There are MANY other programs for different modes - and you should be aware that most folks keep more than one program handy, as there are no programs out there within the reach of a typical hobbyist that can do it all. MultiPSK is a good place to start. The digital decoding article has a link to the Utility Monitoring Central website (all links are blue text) where many of these packages are linked.

It sounds like you have one of those Chinese el-cheapo portables - many of them simply don't have the capability to decode sideband or morse. Save some bucks up and get a better radio - even many ham transceivers these days include general coverage receivers. Educate yourself on the reviews of some of these radios. There's a link in the digital decoding article to our article that has LOTS of reviews links....and don't forget, hamfest season is here!

Time to start reading. best regards..Mike