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Radio Problem


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Hi All


Can someone tell me that if I am experiencing a huge amount of interference - loud static crackling when I transmit but is clear as bell when listening, could this be an aerial problem? I mean if there was a problem with the aerial whether it be it's ground plane, wiring or anything could it only cause a problem when transmitting but not receiving?



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Brent, the radio guy is dumb foundered by it all - we have tried many different tests, engine running, and not, new regulator, different wiring, new radio and much more. At first it was just intermittent and with no common denominator. One thing we haven't looked at is the aerial but I would have thought that if it happens on transmit and it was an aerial problem then it also be on receiving but thinking about it perhaps there is a different loading on transmit that would open itself up to some kind of interference problem.



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It is possible the transmitter could be reacting do a mismatch on the antenna - if its only on certain frequency range the match can be corrected by changing the coax length or antenna. Its more likely to be a fault with the coax ground connection. Similar problem the other day here:


Posted: Sat Aug 25, 2007 1:39 pm Post subject: Re: Radio problem! PROBLEM SOLVED!!! The BNC connector at the antenna was gounding out. I made a whole new cable for good measure, and all the problems are long gone!!! Thanks for all the advice....






</SPAN>mprather(at)spro.net wrote:If you speak into the mic while transmitting, do you hear your voice (from


the sidetone) through the headphones? Are other stations able to hear


your transmission? With good quality? In addition to adjusting the gain,


you might be able to adjust the sidetone volume if everything else appears


to be working properly.
















I have an XCom radio in my RV-7A and I am having some problems


transmitting. I seem to receive just fine. When I push the PTT button on


the pilot control stick I get a static in my headset. If I push the PTT


button on the passenger control stick I get the same static (in the pilot


headset) with the same intensity. When I switch headsets to my backup


headset I don't hear the static when I push the PTT. HOWEVER, the problem


is much worse in flight (possibly due to a louder environment); on the


ground with the engine shut down the static is minimal. I have not tried


the backup headset in flight. I will fly tonight with the other headset


to see if this eliminates the problem, but I don't think it will. Since


it only happens when transmitting I am starting to think there is a


problem with the PTT wiring?? Any ideas to start me out? I will report


back with the results of using a different headset. Could this be a gain


adjustment needed (I can adjust the gain)?










Read this topic online here:








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Guest pelorus32

G'day Ian,


I know this sounds simplistic but I have recent experience of this: Is it the PTT? So for instance does it behave the same when you plug in on the RH seat and use that PTT? I reckon a lot of the PTT switches that are used are cheap and nasty. One I fly with needs to be pressed "just so" in order to get a clear transmit.







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Thanks Mike but we have tested the PTTs in many different configs and have the same problems.


Jetboy - what you have posted is EXACTLY what is happening - I will get the radio man to check that out - thanks!



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Drop a pm to Paul Lintott - Zulu 1. He is a wizard with all radios and he has certainly assisted me with appropriate antenna design as well as rf suppression regarding the use of various headset configurations.







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Thanks Perry, went up on Sat after the radio man looked at the BNC connector and all is fixed - finally ;)


This has been an intermittent problem for the last few months with it becoming a constant problem recently - tried everything including even a new radio, new regulator etc - the radio man was stumped.


Gee these forums are great in helping each other out - thanks to all!



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