We had the exact same problem with our 2 meter repeater. Everything that
originated from the repeater (ID's, phone patch etc.) was fine, even on
site (very close) repeated transmissions were clean. But all other
repeated transmissions had noise in them when the wind blew or during high
humidity conditions.
Eventually we found the remote aux triband fiberglass antenna (2meter, 220,
440) about 50 feet away had a bad 2 meter section in it. We were using the
aux 2meter transmitter to link with the repeater in the next county and it
DID NOT have any noise (figure that one out). It wasn't until I got on roof
and shook the aux transmitter antenna on a calm day with a distant station
using the repeater (not the aux transmitter) that the noise reappeared. We
figured since the aux transmitter was clean than it can't be the antenna,
right?- WRONG! So, look for anything that will resonate at the repeaters
frequency, even an unused antenna, vibrate it and see what happens.
Good luck 73.
Cris KE4IIF
At 12:50 PM 4/19/99 EDT, you wrote:
From: SCOMIND@...
Hi Guys,
Our club could use some ideas on combatting a bad crackle in our 2M
repeater.
The site is a mountain top where there is almost always some wind. The
system
has behaved very well for years, but for some weeks there has been a bad
crackle on user transmissions. The crackle is worse during high winds, and
is
only present when the receiver hears a signal. That is, the carrier is
perfectly clean when only the transmitter is up, such as during the dropout
delay or IDs. This leads me to think it is not a bad antenna connection. The
site is very busy, with the continuous addition and removal of commercial
and
public service RF gear. A high-power TX was recently added.
Note that we actually have two identical systems on the same frequency, with
one being a hot standby. The repeaters are on separate towers a couple of
hundred feet apart. The crackle is the same on each repeater! It is bad
enought to cover up many user transmissions.
Thanks for any suggestions.
73,
Bob, WA9FBO
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