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I've been having radio transmission problems on my Dittel FGS-2T off
and on since I put it in. Some people say I'm over-modulate, some say I'm under-modulated. I've got a factory boom mike and a factory wiring harness. I finally got one of those MFJ-259B SWR analyzers to see if it's an antenna problem. At 123.4 MHz the SWR reads 2.4. It bottoms out at around 1.7 at 131 MHz. Question: Should I worry about an SWR of 2.4? If so, how could I possibly tune a built in antenna? Also, anyone have any experience in fixing modulation issues in a radio? Second issue. I have a couple of magnetic mount ground station antennas. They both show a SWR of around 2.1 at 123.4 MHz and a minimum SWR of 1.1 in the low 130's. Question: Should I go get longer whips for these to better tune them for the glider freqs? Note to all of you trying to tune these kinds of antennas - Having them magnetically mounted to a steel roof makes a huge difference in the readings. |
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On Jan 10, 6:00*pm, wrote:
I've been having radio transmission problems on my Dittel FGS-2T off and on since I put it in. Some people say I'm over-modulate, some say I'm under-modulated. I've got a factory boom mike and a factory wiring harness. *I finally got one of those MFJ-259B SWR analyzers to see if it's an antenna problem. At 123.4 MHz the SWR reads 2.4. It bottoms out at around 1.7 at 131 MHz. Question: *Should I worry about an SWR of 2.4? If so, how could I possibly tune a built in antenna? Also, anyone have any experience in fixing modulation issues in a radio? Second issue. I have a couple of magnetic mount ground station antennas. *They both show a SWR of around 2.1 at 123.4 MHz and a minimum SWR of 1.1 in the low 130's. Question: Should I go get longer whips for these to better tune them for the glider freqs? Note to all of you trying to tune these kinds of antennas - Having them magnetically mounted to a steel roof makes a huge difference in the readings. Andy, I went through as rash of radio probems similar to yours, it was driving me and my fellow pilots too ?????? Sometimes it was OK, sometimes garbled, sometimes not at all, sometime overmodulated. I changed radios, antennas, wiring harnesses,and boom mics, antenna wiring multiple times. Even used an external antenna. The only thing I didn't change was the push to talk. I did check it with an Ohm meter many times for continuity and it was OK. It was one of the real nice tactile heavy duty PPT couldn't be anything wrong with it! Out of frustration I finally changed the PPT for want of something to do and because it was the only thing that I had not changed. The problems were solved and I was amazed and in disbelief ? When I opened the PPT up it was green and corroded inside. Replacing the PPT solved the problem. So just because it is simple and has continuity don't assume all is OK. Richard www.craggyaero.com |
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