I've been trying the MFJ-1026 again today during daytime while the band is
devoid of signals and QRN propagated by the ionosphere. I wanted to
concentrate only on my specific local noise source(s). Gone back to square
one with all adjustment and trials.
I think I have determined part (if not all) of the problem at my QTH. I
believe the Main antenna and the Auxiliary antenna are "hearing" two
different noise sources. I think the loudest noise source for the Main
antenna (870' Beverage, in this case) is a line of utility poles that
crosses in front of it about 100 yards distant, while the loudest noise
source for the Auxiliary antenna (dipole) is a single utility pole about
100 feet from the shack. Although, the Auxiliary antenna can certainly
"hear" the same noise that the Beverage hears, it is at a much lower level
than the closer noisy pole.
The last thing I've done is to feed the output from the NE Beverage into
BOTH the Main and Auxiliary ports (as per suggestion from Tod, K0TO), and I
can indeed null the offending noise completely out. However, this
arrangement also attenuates any desired signal from the Beverage the same
amount as it attenuates the unwanted noise. I checked this out in the AM
broadcast band on a station about 30 miles away. After nulling the noise
slightly off frequency, I tuned the station in on 1580Khz. With the 1026
off, their signal was S9, with the unit on, they were S4. That's 30db down.
But, at least I know the unit is working.
I'm not looking forward to the prospect of installing an identical Beverage
antenna alongside each existing one in order to make sure both ports of the
1026 "see" the same noise. Maybe this would be a good use for a BOG, since
the noise is local and strong.
Any additional suggestions, anyone?
Charles - K5ZK
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