My recent efforts at putting a 220 repeater on the air here in western
Florida have been mildly succesful. I am using a Neutec designed repeater.
( I know there are some uhf and vhf models around, this one is on 220, a
RANGER brand ). The repeater is open access. And runs quiet all day or
night, nothing cracking the squelch at all. But during times when there is
a conversation going on after a few minutes a rather nasty signal captures
the repeater sometimes in short bursts, sometimes much longer. "Sounds like
someone talking into a reverb chamber.." I had been using a Mirage brick
amp in the rack, but suspected that this amp might be the problem, some
oscillation or internal mixing of some sort. This turned out not to be the
case, the amp though still in the circuit is OFF but we still get the
garbage. When the amp would be ON, and I would sometimes hear this stuff
start, and I could turn OFF the amp an it would stop. But shortly later
even with the amp OFF, it is back.very odd that it would appear to me.
Now, all cables in the rack are RG-400. Every one in the rack. Half inch
hardline runs to the antenna, though there is a splice with a double male N
connector as I recall. The Neutec unit does about 25 watts output but I have
it cut back to about 10 watts thinking it will run cooler. Thus with the
small brick amp it was doing about 65 watts output to the Telewave 4 cavity
duplexer.
While at the site tonight, I could hear something getting into the recvr.
The repeater was UP, but no one talking at that moment. Again, nothing on
it's own ever appears to break the squelch. The noise was heard through the
repeater's on board speaker, meaning it was coming through the antenna /
recvr and not something produced in the rack I would assume.
There is a cel tower about 1,000ft away and another tower with ( who knows )
how many other users, another 500ft further away. Based on this little bit
of info what would the masses suggest in first FINDING the offending source
if is indeed intermod? Then, is there much than can be done short of
moving my machine? Any ideas or suggestions?
n Mike
