Radio GAGA

[I.R.PIRATE]

Hey there folks, was just wondering whether anyone out there had any advice.... Flying today, and found that both my comm boxes would give me a very high pitched whine, and the incoming transmissions were totally unreadable. Problem is....it only does that on ONE specific freq, all others are fine???????? No other pilots reported the same problem, so now I need to know if anyone has any idea what could cause that?? Both box 1+2...same snag????

[RichT]

I can’t answer the question for you but maybe a few tips to the problem. 2 boxes doesn’t necessarily mean true redundancy.

Are the boxes exactly the same (manufacturer/model etc).

How repeatable is the problem: Can you get this to happen on the ground and outside the range of the transmitter on the offending frequency.

Is the freq at one end of the spectrum.

Are there any other possible factor for example the freq is close to the freq set on the nav box at the same time (I am thinking of some kind of harmonic interference in the AF stage). Have you tried different headsets?

[I.R.PIRATE]

Thats actually the very interesting bit...it is a general air to air frequency, 126.325, and the problem is present whenever one of the radios are tuned into that freq. Yes they are the same make and model comm sets. Somebody else mentioned that problem to me today, but said its only when in a certain part of the country, so i guess there might be some interferance from an external source somewhere, cause afghanistan must be humming from all the radio and who knows what kinds of transmissions filling the airwaves.

[barit1]

Possible answer: Is there a digital computer on board with a 120 Mhz clock speed? I once encountered a engine with a 120 Mhz FADEC.

What were they thinking?????
:ugh: :yuk:

[ShyTorque]

Used to do this on the military Puma and was due to water ingress (see the black bodge tape over the nose bay on some RAF aircraft). Also, can occur in the SK-76, probably caused by static in the atmosphere.