Bearcat scanners are notorious transmitters. Try listening on 136.83 and 158.43 for a carrier on your repeater receiver 147.63. Try other combinations of plus or minus the scanner IF freq of 10.8 mhz.
Gary K2UQ
Then try plus or minus 10.7, 11.7, and 21.4
The most "interesting" example of a broadcasting local
oscillator was reported on a Chicago 220 repeater about
20 years ago. The repeater (carrier squelch) was located in
the equipment room on the top of an office building. Every s
o often the repeater would unsquelch and fade in (as if
ramping up the TX power) play a local radio station quite
clearly, then anywhere from 30 seconds to an hour or two
later it would slowly fade out (not suddenly drop off) and the
squelch would close. There was no pattern except that it was
most often in the morning and evening, and would rarely happen
on a week end, but when it did it might last for hours.
To make a long transmitter-hunting story short (it took a couple
of months), the source turned out to be a harmonic of the local
oscillator of the FM receiver in the elevator car of the same office
building where the repeater was. The FM receiver was on the
roof of the car, and powered by the lighting circuit. Only when
the car was within two floors of the roof did the problem happen,
the second-to-the-top floor was only partially rented, and the
top floor was storage and air conditioning. The control system
of the elevator was relay based and left the car at whatever floor
was it's last destination. The assumption was that the receiver
filter caps were a little old and the LO was being slightly
modulated by the received audio.
The cure? Twist the knob to change stations on the FM receiver.
I had a similar situation as I was driving down the highway
one day. My UHF Micor receiver (on 445.xxx MHz)
unsquelched and I started to hear a FM station. It got stronger
as a new Toyota Cressida pulled along side, peaked as it
passed me and then squelched as the car reached a distance
of about 5-6 car lengths ahead. I was not in a hurry so I followed
it off of the next ramp and then into a fast-food chain restaurant
parking lot. The Toyota's driver went inside, I pulled into a nearby
parking spot and as I walked inside to get a drink I walked past the
Toyota and looked at the dashboard - a brand new Sony high-end
aftermarket receiver. Oh well, that's what PL on the repeater
output is for...
Mike WA6ILQ
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