Tom wrote:
> Ford actually said the noise stops when the furnace starts! That changes
> everything.
>
> 73 Tom
Tom is right. Many respondents have urged me to check this or that and I
have killed the power to the entire property with no effect on the noise.
My nearest neighbor is about 1/3 mile away. Disconnecting power to the
house, the barn, and the shack have had no effect on the noise. But when I
listen on the 706 in the car, lots of similar broadband hash noise on that
power line out by the road and within 30-40 feet of the barn. If I drive
within 60-80 feet of that line, the S meter with the attenuator on goes off
scale (the 706 is notorious for having a very generous S meter).
To add insult to injury, something else has changed. Very strange weather
in MN this year. No snow! Until yesterday afternoon. It snowed and the
phenomena has ceased to be repeatable. The noise is still there at S4 or so
on topband, but the motor starting no longer has any effect. My petre dish
is gone but the phenomena was there over the weekend and until yesterday (I
spent hours listening during NAQP). That fan must have started 100 times!
Several encouraged me to investigate current flowing in ground straps at
service panels. This is my next area of investigation. I'm thinking that
the snow has changed the dynamics of whatever was (and possibly still is )
happening here. 8 ground rods in frozen (parched and freeze dried) soil,
distributed over about 5 acres, may be sensitive to induced fields from the
nearby power line. I'm going to try looking at the barn wiring first. The
barn is in the shadow of the 66kv powerline, and has several long runs of
electrical wiring running in parallel with that line for possibly hundreds
of feet. Induced fields may be getting back through the neutral and safety
grounds. Those long lines of wiring may be inducing WATTS of energy into
the ground system.
I haven't plotted it yet, but my intuition and experience tells me that the
noise seems to be directly proportional to the load on that power line. The
colder it gets, the worse the noise. Likewise in the summer, when A/C goes
into overdrive around here, the hotter it gets, the worse the noise. Perhaps
the line is unbalanced and inducing a field that just happens to have
wideband hash associated with it?
I think I'm going to try decoupling the barn from the rest of the wiring on
this property.
I will also fabricate a clamp on bead with several loops of wire, hook them
to some feedline, and run them from the ground strap on each building back
to the IC706MKIIG in my pickup. Maybe I can buy another clue...
Thanks for all the help and the bandwidth. There must be a thousand years
of experience helping me investigate this. I thank you all.
Ford-N0FP
ford@cmgate.com
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