Topband: MFJ-1026 Noise Cancellation

[Charles Bibb]

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