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There are two separate issues - at least. A dipole antenna is simply a 1/2
wave antenna fed in the middle, so that a 1/2 wave is on each side. In effect, each half element reacts with the other half. A 1/4 wave ground plane simply replaces one of the elements with a plane perpendicular to the other. The second issue is polarity. It just happens that many dipoles happen to be mounted horizontally, while verticals are mounted vertically. A dipole can also be mounted vertically. Polarity should be the same or there will likely be a severe signal decrease between stations. By convention, aircraft vhf communications is vertically polarized. It is difficult to analyze your problem with the sketchy information given, but basically an antenna is an antenna. If your 1/4 ground plane does not work at all, a dipole will not work, either. Replace of one with another will simply postpone finding the real problem. The most likely problem is the antenna connectors. Unless they are assembled correctly, the entire system will fail. Even though the location of your antenna may not be the best, it should be adequate for what you want. Your champ is a fabric airplane, so you will need a "ground plane for the 1/4 wave vertical. This can be as simple as a 24" wire attached to the base and extending out. In fact, that will turn it into a dipole. But even that will not cure a bad connection. It is also possible the radio has a problem, but I would not expect that. Find someone who can assist you to check things out. It is very difficult to diagnose the real problem without being there. Colin N12HS |
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Correction: Each half of a 1/2 wave antenna is a 1/4 wave. I was suffering
from moderate hunger when I typed the response. Colin |
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