UHF ch 40 interference

[lefty]

there is something in the Foz that is interfering with UHF channel 40 (477.400mhz). All other channels are fine.
I have 2 handheld UHFs and it happens on both.
The only aftermarket gizmos I have is an amp and subwoofer running off the stock stereo , and a mechanical boostgauge.
I have pulled the fuse for the amp but no luck.
The interference only occurs when the key is turned to on , not acc and continues for about a minute after the car is turned off and locked.
any ideas?

 

[Scooby2]

Hi lefty .... this may be a long shot, but it sounds like something to do with the transponder chip in your key communicating with the ecu for start up and shut down immobilizing of your car. Specially if it happens every time you switch on and off.
Regards, scooby2

 

[lefty]

the strange thing is it has never happened before and I've had the car since 2005, if it was the transponder I would have noticed a few years earlier?

 

[Scooby2]

I'll try and ask some questions tomorrow. There is an aerial around the ignition which transmits the signal from the chip in your key to the computer in your car... Maybe the aerial is loose?.... Or, page 3 of this link may have some info on channel interference on UHF channels that may shed some light on your prob

https://www.gme.net.au/public/pdf/manuals/tx3100-3_im.pdf

Some long shots, but mysteries don't get solved usually unless you think outside the square!