On one repeater frequency at my QTH, the noise over-rides the signal.
What is the signal strength on your S-meter?
It is quite possible possible that you have a local noise
source that is covering up the repeater signal.
If the signal is full scale, that is likely the case. Then
you need to eliminate the interfering signal. It might
be a wall wart or other piece of electronic equipment in
your house.
If the signal strength is below half scale, then it could
be a weak signal from the repeater.
Does the signal strength or readability change with the
modulation on your received signal?
That is a sign of “multi-path”, where the signal arrives
at your location via two different paths, at about the
same strength. Depending on the path lengths, they
might be in phase (so they add), out of phase (so they
cancel each other), or somewhere in between.
And, yes, that changes with frequency, so it can be
different for the transmit and receive frequencies.
In that case, moving your antenna a foot or two
in any direction can totally change things. At one
traffic light on my commute, moving the car about 3 feet
was enough to change from “transmit but no receive”
to “receive but no transmit”, and I had to carefully
find a point in the middle where both worked when
I was stopped there.
Using a beam may change the relative signal strength
of the two paths, so they don’t cancel each other as
much.
...All other repeaters, even further away are fine...
Distance depends on a lot of factors, including local
blockages, antenna height, etc.
How low can you set your transmitter power and still
have a good signal into the repeater?
If the repeater is hearing you just fine, especially on
low power, then higher antenna gain may not be
the answer.
1) Keep my vertical, plus install the yagi below it, run a SEPARATE cable to the shack and switch between the two in the shack. The yagi would remain stationary pointed at that useless SOB repeater.
...
Your thoughts.
I’ve used fixed yagis in the attic in other situations
where I needed more gain for one particular repeater,
and it worked well. Home brew beams (yagis or quads)
are cheap to build (especially if they don’t need to
survive bad weather).
If you want to test whether a beam will help, you can
build a cheap one and try it temporarily while standing
on the roof, which shouldn’t be an issue for the HOA.
That will tell you whether it is worth pursuing. You
can also see how much difference it makes when you
move the antenna a foot or two. (And we can provide
designs for simple beams if you want.)
But the important first step is to analyze the symptoms,
particularly the received signal strength, to figure out
why you aren’t hearing the repeater well, because
without that information, we’re just guessing at what
how to fix the problem.