[ICOM] Help with Severe Electrical Noise

[mikea]

On Fri, Feb 29, 2008 at 02:09:36PM -0600, michael morgan wrote:
> I am sorry this is not directly related to Icom radios except the usage of
> them.  I have an Icom 756Pro II that I am using with a Gap Challanger
> antenna.  Also has been well for the last few years.  For some reason about
> three days ago and started getting a s9 or higher "White Noise" on all
> bands.  It is over powering all but the strongest of signals.  The is
> happening on all bands.  I have tracked it down to something electrical
> around my desk.  I did this by the following means. If I power the radio
> from a 12V marine battery and kill the breaker to  my Shack area the noise
> diminishes.  If I power the breaker back on the noise returns.  I tried to
> unplug everything with the breaker on and I get the noise.  I am stumped.
> It is there if I power from a battery or my 12V power supply.  I
> disconnected everything from the rig exept power and antenna and it is
> there.  Any help would be greatly appreciated.  Also this is occuring on my
> other rigs as well which are a Icom 706MKIIG and a Kenwood ts450s.

Let's call that breaker X. 

Got any Ground Fault Interruptors (GFIs) wired into the stuff downstream
of breaker X? If so, you might want to cycle each of them. 

If the noise persists with everything unplugged that's downstream of
breaker X, and still comes and goes as breaker X is turned on/off, it
may be time to call in an electrician, because something's happening
in your power wiring that shouldn't be happening. With everything
unplugged, there shouldn't be *ANY* noise downstream.

Can you turn the rest of the house off, too, at the individual breakers, 
and see (A) if the noise still comes and goes as you turn breaker X on
and off, or (B) if the noise is gone with all the rest of the house off
and breaker X on, if there's another breaker that causes the noise to 
reappear? 

Stuff like this is hard to find, sometimes, and worrisome, too. 

-- 
Mike Andrews, W5EGO
mikea at mikea.ath.cx
Tired old sysadmin