I made an attempt at the NAQP-CW today. Great fun. During the evening
hours, I noticed something about noise on 160M and 80M that may help me
achieve better S/N.
It's very cold outside--about 0 degrees F. When the blower on the shack
furnace kicks on, my noise levels dropped enormously. The noise is a "egg
frying" hash type. My noise is not bad. S0 with the 500 Hz filters on.
The improvement in noise can only be observed when the 1/2 horse motor is
starting. It will last for about 2-3 seconds. Topband signals will pop
right out of the noise and disappear once the blower was up to speed.
Whatever is going on, I want that experience all the time, not for 3 seconds
every few minutes.
The blower motor is a generic single phased 1/2 horse. When it starts, it
must throw an inductive load on one side of the 220 line (it's a 110v
motor). I don't think the noise is determined by which side of the line the
furnace is tied to, it only happens during start-up--the noise is there when
the fan is off. I don't think it is a voltage issue, since the rig is
powered by a 12v/50 amp power supply. On receive, a total of what, maybe
400 ma draw? The lights in the shack don't flicker on start-up. I've never
noticed anything strange about the wiring arrangement before.
>From the 6.6kV mains at the street, there is a pole pig in front of the
property to drop the voltage to 220v. The transformer is on the main pole
and only services my property. All the local wiring is buried. From the
power company meter, the service splits to feed the house in one direction,
and the shack in another.
I'm thinking this is a major clue as to how to minimize my noise. A filter
at the shack service panel? Why would an inductive load on one side of the
local line reduce my noise significantly?
Once again, I turn to the repository of all knowledge--topband for help.
Ford-N0FP
ford@cmgate.com
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