2 Channel Radio-Sound Card Interface


I wanted to build my own 'stereo' radio-sound-card interface so that I could run two radios at the same time, and control both channels from the same serial port using RTS and DTR. Some programs available out there can make use of this set-up, others not.
RadioSoundCard3.jpg
BoxOpen.jpg
This setup has worked for all the hand-held radios I have tried, so far. I had to build a special cable for my Icom IC-T7H which uses a 'stereo' female connector for the Mic and Speaker jack. The 'ring' of the stereo inputs are used when programming the IC-T7H.

On all the information out there (check out the links below), I find that I get the best results when I use the 1:1 ratio, 600 ohm audio transformers. Your results may differ.

Transformers.jpg
Transformers2.jpg
InsideJacks.jpg
InsideSerial.jpg
The plastic project box was used because its the same size as the 1200 baud Baycom TNC that it sits on top of.

The circuit schematic shows male 3.5mm and 2.5mm connectors, but if you put it into a project box use female 3.5mm and 2.5mm connectors instead.

RadioSide1.jpg
SoundCardSide.jpg
RadioHookUp.jpg
SoundCardHookUp.jpg
To connect the radio to the project-box you will have to build some cables. Use stereo audio cable, 2-conductor cable w/sheild. Each end will have a 3.5mm jack for the Speaker connection, and a 2.5mm jack for the Mic connection.

To connect the project-box to the computer you will need two 3.5mm stereo cables for the input and output.



Here are a few links that are worth checking out for more detailed information on the subject:


These sites have links to Kits and Pre-assembled sound-card interfaces, which really don't cost much more than building your own. So unless you like building your own...go buy one.

Info on soundcard interfacing: http://www.qsl.net/wm2u/interface.html

Info on setting up and using software with the Radio-Sound-Card: http://www.soundcardpacket.info/

APRS: http://www.ui-view.com/

Other software sites: http://users.belgacom.net/hamradio/


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