[amsat-bb] The FT-847 and spurious radiation

[Phil <phil@xxxxxxxxxxxxxxxx>]

Hello All,

I wonder if other FT-847 users are experiencing the following problem and if 
there is a cure.

I've noticed evenly spaced carriers across the 144 MHz band. The source of 
this spurious radiation is the microphone lead, no doubt, caused by the up and 
down signals to the radio's processor.

Not only does the radio pick up it's own signal but other nearby 146 MHz 
radios are also effected. The radiation is greatest at the plug end of the 
curly cord. A ferrite choke reduces the radiation from the cord but doesn't 
eliminate it.

I have checked earthing screws on the printed circuit boards and anything else 
that might have been loose. Eliminating extra aerial cable from the operating 
room reduces the signal to an almost manageable level. Even so, the spurious 
signal is barely mutable, which adds to my difficulties with weak FM repeater 
signals. Digipeating via NO-44 would be a problem if the microphone was left 
plugged in.

The FT-847 FAQ does not address this problem so I wonder if my radio is any 
worse than others or if this a normal situation?

-- 
Regards,
Phil
phil@spiderweb.com.au


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