I think one overlooked factor may be the proximity of (home)
antennas to computer equipment.
At my home, we have a 35' height restriction and I have only
a low 135' ladder line fed dipole for 40/30/80 running over
the shack and most of the house. We have several computers
(wife, son, me) and I do get some noise (including from an
Envision 17" flat CRT on my PowerMac).
I contest from the desert QTH and there is so little noise of
any type (even on 160). I generally use a laptop there,
but antennas are not near the shack and I never had a noise
problem with any computer equipment.
On Thursday, January 9, 2003, at 01:51 PM, Leigh S. Jones, KR6X wrote:
> Frankly, I've operated a number of contests at several different
> radio stations with numerous different monitors without ever
> hearing emissions from those monitors. Except, I have always
> heard my own home computers and other electronic equipment
> in my house. This is odd -- I'll go to several different Multi-op
> stations with multiple monitors of different and makes and models
> and none will seem to cause trouble, then I'll come home and I
> can't even drive up my driveway without every AM broadcast band
> station being completely covered by garbage that clearly comes
> from within my house -- even though not a monitor nor television
> is powered up. I've come to expect it. The VCR's put out big
> garbage on 75 and 40 unless you unplug them -- the power switch
> doesn't help. My DSL modem is probably responsible for radiation
> that could be heard across the continent if you know where to listen.
> And, I've got 6 computers under power at all times and 3 more that
> turn on and off with use, what with primary domain controller, backup
> domain controllers, e-mail server, web server, personal workstations
> and home security monitoring computers all around the house. FRI
> nightmare. Can't do contests from home anymore.
See my web page: http://www.k7on.com