> Hello all-- I am a new subscriber to this reflector and
> have a problem
> --ie.I recently replaced my FT-1000 MP with a new FT-2000.
> I changed
> nothing--cables,ground system etc.but the new radio gets
> into the TV,
> security system,computer speakers etc..I have high / low
> pass filters in
> the proper places,toroids/chokes,wherever I can put them.
> Put in a new
> 8' ground rod etc.
Bob,
First let me say Howard has an excellent suggestion. Swap
the radio out very carefully with NO other changes and see
what happens.
Now let me interject a few things that deal with some common
Ham myths and misconceptions.....
1.) The ONLY possible reason to need a ground rod in a
system with proper antennas is for electrical safety. A safe
installation requires the ground system be bonded to the
power mains ground rod outside the house. There is
absolutely NO reason, RFI wise, to ground the station unless
you have an antenna system that creates significant common
mode currents on cables. If you have this problem don't
band-aide it with grounds and special wiring, fix the RF
ingress coming back down the cables.
2.) Shield connections at each end of the RF cables are
hundreds of times more important than the routing of cables
or the quality of cables, assuming the cable is even
reasonable construction. A single shielded cable with even
"80%" or "90%" shield coverage will cause virtually no
problems if the cable has good connections at each end. RFI
is normally caused by substantial problems, like an open
shield or a poor antenna design.
3.) There are also certain pieces of equipment that cause
problems, one that comes to mind is an antenna tuner with
paint under the screws. One friend of mind had a tuner that
actually intentionally insulated the case of the tuner with
insulators!! The designer intended that to reduce losses,
but that was sheer nonsense. All it did was cause RF in the
shack.
If you only changed the radio and disturbed nothing else and
now have RFI problems, and if you don't have them with a
dummy load, you probably have two things going on:
1.) You always had an antenna common mode current problem
but had it hidden by a lucky layout. You perturbed the
system and your luck went away.
2.) The radio might have a loose or poor ground on a coax
connector or the cable connecting the radio, or perhaps you
loosened up another RF cable when you moved the radio.
Many people just throw changes at a system and think they
magically "fixed" a problem, but what they really did was
find a way through accidental "monkeying" to make the real
problem reduce in level enough to stop affecting a device or
devices. It's an absolute fact that an RF ground is not even
required if the antenna system up to the connector on the
radio is proper. Even with cheap coax.
73 Tom
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