CABL Forum - Re: Antenna Interference

trilithic at one time made a system for locating such interference
i don't know if they still make it or not
the outfit consisted of a unit similiar to a searcher cli meter
it had an output for attaching an oscilloscope to verify the 120hz
it also had a handheld antennae for directional location.
with the system you could locate some "micro gap discharge"
thd kit also included a worksheet to calculate if what you found
was interfering
you had to start with the signal at the headend off of the off air
antennae
then get the polorazation charts for the off air antennad and
insert the loss from that and the noise level to determine if
that was a possible cause
i never had any luck with the local power company helping to
find the problem
start by going the direction that your off air antennae is pointing
if the stations are local with a strong signal, then expect to find
your source close to the headend, maybe a 1/4 mile or so
if you locate noise at a 90 degree direction from your antennae,
then chances are , due to the antennae polarazation chart,
that is not your problem
any metal to metal contact can cause this, supposedely including
chain link fences and gutter downspouts, but suspect corroded
hardware on poles, not necessarily power hardwarte either
i found that just loosening phone and cable bolts and retightening
helped reduce this.
chances are you will find multiple sources for this, especially if you
see sparkles inbetween the two bars.
the am radio trick may work or a cb, especially if they have a signal strength meter on them.
a spectrum analyzer can also work since i have seen this
"micro gap discharge" go up beyond 200 mhz
good luck

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Re: Antenna Interference