[Scan-DC] mode question.

[Andrew Clegg]

Just a wild guess here, but it could be an image frequency. Given the typical IF used in scanners, that frequency would likely be an image frequency for signals around ~133 MHz in the aircraft band. I have a scanner that is very susceptible to exactly this type of image in the 155 MHz band, and when planes are overhead, their signals can be quite strong, and the audio comes in very distorted. Can you tell roughly what type of communications it is? How often do you hear something? Is it usually male voices (sorry, but the majority of pilots are still men), does it otherwise sound like some kind of aviation communication (usually as brief as possible)? Can you possibly have another scanner searching the 132-134 MHz band at the same time, and see if your distorted signal corresponds to any communications in the aircraft band?
 
If your scanner uses a typical 10.7 MHz IF, you may want to search specifically at 155.355-2*10.7 = 133.955 MHz (or the closest valid aviation channel to that frequency).
 
Andy
 
> Date: Tue, 12 Nov 2013 05:05:47 +0000
> From: odyslim at comcast.net
> To: Scan-DC at mailman.qth.net
> Subject: [Scan-DC] mode question.
> 
> 
>  I was cruising the bands for new freqs. Using my Icom IC-R100 monitor,
> it stopped on 155.355. I can hear voice but cannot get anything clear. 
> I have tried AM, FM, FM wide and nothing will bring it in. I have also
> tuned around that freq and nothing will clarify the signal. I am guessing 
> it is encoded.  Any thoughts?
> 
> Scott W3CV
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