Originally Posted by
Neil
It is surprising how well a cheap radio will work if it is connected to a good antenna that is properly installed. The simple rod type whip antennas will work as good as any for about the first 100 channels, then it starts loosing ground. That's why they are under 20 bucks. For a belly mount the AV-17 from R. A. Miller and the Comant Ci 122 work pretty good for the money. These antennas are wound which I'm told broadens the channel range significantly. The antenna must be mounted to a satisfactory ground plain. Most Biplanes have a large enough alluminum belly panel to create a good ground plain. A minimum ground plain would be about 18" in diameter. Try to keep the antenna far enough back so it isn't blanked out by the landing gear. Don't scrip on the antenna coax. The RG-58U has been used for years and works pretty good but the RG-400U is the new kid on the block and is a better cable, particularly for transponders. Have someone that has the proper tools make up the coax. Many transmit/receive problems come from improper connections.
I have a King KY 97A connected to the AV-17 on the bottom of my Acro Sport and it works well. Even sitting inside a metal hangar with the door down I can talk and receive with airplanes flying overhead