Topband: Shack wiring & noise

[Ford Peterson]

Wow!  Lots of good responses.  Most want me to disconnect the furnace fan.
Well, I just completed a better experiment.

The "shack" is a separate metal building on my property with it's own
electrical panel and ground system--all tied into the tower ground.

I went out to the camper and uninstalled my deep cycle battery.  The battery
is now powering my radio.  With everything I can locate in the shack off--no
computers, phones, only lights.  I went to the main 100 amp breaker and
switched it off.  There was absolutely nothing but my radio, my flashlight,
and my wrist watch running within about 200'.  No smoke alarms, no wireless
internet, no electric clocks.  Nothing!

My rig was tuned to 1842.  No attenuator, no filters.  My noise tonight
bounces between S3 and S5 with a relatively steady reading at S4 (power
applied to lights).  After throwing the main breaker, there was no
perceptable difference in my noise floor.  I conclude that the noise floor
is not determined by anything in this building.  After turning everything
back on, the noise floor is still unchanged.

Of the many private emails (thank you) one respondent recalled that the
power company uses capacitors along the length of a long line to change
power factors.  Here is what Doug wrote privately.
*********************************************************
Several things in your email rang a bell with me, so decided to answer for
whatever its worth.  Having been a telephone engineer most of my life, I
have done alot of co-op work with power companies in noise mitigation.  Long
power line feeds become so inductive that the power companies add capacitors
at strategic points to improve their power factor.  These created and
amplified harmonics that were induced into adjacent telephone cables.

This gave me the idea to tune my house wiring with a big electrolytic
capacitor.  This illegally slowed down my power meter, rather than saving
electricity, but I noticed strange new buzz's created on shortwave, as the
capacitor was plugged into the line.  In the right circumstance, a capacitor
could also eliminate a buzz.

If your motor has a starting capacitor, that could be detuning your buzz, as
well as the throwing in of inductance, as you suggest.
*********************************************
I must conclude that one of two things may be happening.  1) the noise is
being conducted through the ground system--a ground rod at each building
entry point (I count 7 sprinkled within about 300' of this building's
ground), or 2) that little itty bitty capacitor in my furnace fan motor is
detuning some noisy condition nearby--possibly with the ground itself.

Throwing breakers is one thing.  If the noise is conducted through the
ground system, well... Here is what I cannot disconnect:

>From the power pole transformer, a wire runs down the pole to the ground
(~35').  Buried cable runs about 130' to the meter location.  At the meter
location is a large junction box for separate buried line runs to the barn
(SW~80'), the house (E~ 80'), the shack (W~75'), the garage (NW~80'), and
from the garage out to a metal pole barn (N~200'), up overhead back to a
Quonset building (SW~50').  Each building has an 8' ground rod at the demark
point for some lightning protection.  No, I'm not going to unscramble that
junction box--it sounds like a good way to die.  The conductors are as big
as my finger and stiff!

In each building (most notably the barn, which is in the shadow of the power
lines.  BTW the main breaker to the barn was tripped for my little battery
experiment), there are numerous runs of romex for lighting, each run being
elevated well above the surface of the ground and each having a separate
safety ground and a neutral line--none of which are switched by any breaker.
All the neutrals are connected back at the junction box of each building and
an 8' ground rod with #4 copper connecting to each of the separate breaker
panels.  Other than the house, none of the other buildings have any
equipment other than unused outlets and lighting circuits (all off).

Is it possible that this complex connection of "grounds" is able to
resonate?  I can't figure out what else I can do with the grounds to beef
them up.

This is a head scratcher.  Maybe I'll just get an identical motor, stall it,
and activate a foot switch for minimum noise after a CQ? hihi

Thanks for the help guys.  If I can just buy a few more clues!

Ford-N0FP
ford@cmgate.com