Hi Steve,
> A good friend of mine who also enjoys 160m recently moved from a QTH that
> had a very low electrical noise level compared to mine, to one that he
says
> is so quiet on Topband that he is sometimes unsure if the antenna is
> connected. In this case, power lines are underground and all the local
> properties are on small acreages and well spaced out.
I can vouch for your friend's claims. I have to be careful here to be sure
I have the correct antenna connected, no way can I tell by the S meter
alone.
I'm on a rural (one lane dirt) road miles from power line noise sources and
dense population. Daytime 160 noise level, even on a 200 foot tall
omni-vertical,
lets the S meter lay on the stop. I can actually hear an increase in noise
on my four square when I point it at two small town's about seven miles
away, but all the verticals (during daylight) are so quiet the noise
doesn't move the meter.
What a difference from Rockdale county, where noise was about 30 dB
higher than here during daytime on the vertical.
(I'm going by actual dB, not S meter dB. All of my ICOM's are about one dB
per S unit between S1 and S2, climbing to the "official" 5 dB per S unit at
S7 or so.)
Unfortunately, a low daytime noise level quite often becomes meaningless.
When the band "opens", noise comes way up. Even on a very quiet day (no
QRN) my receiver noise level increases almost 20 dB when the band "opens".
That is the big equalizer for all reasonably quiet locations. Noise
propagates in via sky-wave, at dusk or dawn I can tell what direction the
band is open just by watching the background "hiss" change in various
directions.
The effect of this is, barring thunderstorms, is that stations in quiet
locations can hear MUCH better than they can be heard during daylight hours
when the band is just barely open in one direction. I've heard VK6HD, TL5A,
and Europeans hours before dark here (G3SED once just after lunch time!)
but they sure can't hear me no matter how I call. It isn't "one way skip",
it's just that I'm listening with almost no background noise and they are
in "full" propagation with much higher local noise.
Some days a quiet location is no advantage at all, others it is a big
advantage. I've been totally surprised how much propagated noise (and QRM
from amateur and broadcast transmitters) becomes a problem after local
noise is removed from the equation.
Quite often during darkness the 4 square is the preferred receiving antenna
and the horiz is almost useless, the exact opposite is true in sunlight
when the band is coming in or fading out. After the band is out or in, the
vertical takes over again (the Beverages behave like the 4 sq)!
Another really neat thing is in daylight, on days when the high horiz
antenna totally dominates, the verticals AND Beverages go totally "dead"
for both noise and signals. The phased dipoles will be much "noisier" than
the verticals during that time period. This whole thing is pretty
fascinating, since quite obviously even short distance signals go
through a daylight change where either wave angle or polarity (or both in
combo) totally "kills" antenna response, and that response varies by the
hour and day.
73 Tom
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