Radio coverage drive test + audio log

November 2, 2003

For sound card amateur radio modes a simple SoundBlaster USB soundcard as the ADC & DAC on the built-in sound card didn’t have adequate SNR. With the Icom IC-725, PSK31 works quite well on the USB sound card–since I don’t want to splash 3 kHz at 10 mW of internal soundcard hash on the air. On CB 27 MHz it’s hard to talk to base stations 25 km away during the day–a striking difference from a few years ago when the sun was quiet. But this means a boon of DX on ham frequencies.

Radio Coverage Map verification and range test of such radios is as follows: put the base station into VOX mode, and setup the PC to play a tone N seconds long every M seconds. Then, setup the PC to simultaneously record continuously (or use a separate recorder).

Now you have a timed radio coverage system–synchronize your watch and PC clock. Then, even for the maximum range case where your base will hear the mobile but not be able to understand it, because you record your location vs. time in the car, based on the number of beeps you can match unreadable transmissions with where you were–which is often more important than where you can hear!