Randy: If you don't have a phase coupler,
I would go with that (I wrote a detailed
description of phase coupling in the
general forum). A passive coupler is
adequate for most people, but if you have a
large house, you may want to use a
coupler/repeater instead.
If you already have some type of phase
coupler, then I would check for something
that is either generating noise or sucking
up signal. Unplug (don't just turn off)
fluorescent lights, electronics (TVs,
Computers, Stereos, etc), power bars and
UPSes starting on the same circuit and then
extend out to the same phase and then to
the rest of the house and see if it starts
working. For other circuits you can turn
off the breaker if you prefer. Once it
starts working, start plugging things back
in and see what causes it to stop working.
Put an X10 filter on everything that seems
to cause you problems.
Only if you are still having problems after
all that (and you have a coupler/repeater)
would I bother with a plug-in signal
booster. You could also give it a try if
you seem to need lots of filters to try and
reduce the number needed.