TO: ALL WOOD COUNTY EMERGENCY COMMUNICATIONS AMATEURS
ALL NON-WOOD COUNTY EMERGENCY COMMUNICATIONS AMATEURS
FROM: KEN HARRIS WA8LLM
WOOD COUNTY EMERGENCY COMMUNICATIONS INCORPORATED
WOOD COUNTY BULLETIN NR 13.13 DATE: March 31, 2013 SUBJECT: THE SOUNDCARD INTERFACE
In the last bulletin you learned what a soundcard is; now you will know how to use it to connect it to your radio for digital communications.
There are a couple of ways to connect your computer to your transceiver to take advantage of soundcard programs. Some of the older desktop and laptop computers had a serial port in the form of a 9 pin plug. Using certain pins on the plug you could connect them to the Push-To-Talk (PTT) of the transceiver, but there is an easier way.
The audio tones coming out of the computer soundcard jacks can be used to operate the transceiver PTT. The audio coming out of the soundcard jacks can be amplified to a higher level using a soundcard to radio interface. Since the higher level tones are in the form of an Alternating Current sine wave, they can be converted to a Direct Current (DC) signal. The DC signal can be used to cause a transistor to operate the transceivers PTT.
A sample of the computer soundcard audio tone can also be sent to the transceiver microphone jack, to be transmitted of the air. When the computer is being used to receive audio from the radio, all it has to do is go back into the microphone, or line in jack of the computer, and the soundcard program converts the tones back into written words.
The computer-to-transceiver interface is a very simple unit and it can be either purchased or build. In any case using soundcard programs can be fun, and with the proper Amateur Radio license, you can communicate around the world with very little power.
Ken Harris WA8LLM
WCEC
Wood County WV