Topband: MFJ Noise Canceller 1026/1025

[Herb Schoenbohm]

Wanting to try to phase two end to end Beverages I took several MFJ 
Noise Canceller 1026 and 1025 of the shelf and while trying to evaluate 
their ability I noticed on both unit that even without any antenna 
connected to either input there is a least an S-unit increase in 
background noise.  One of the units has a built in pre-amp that that was 
switched off.

My question: Is this normal?  Won't that noise increase mitigate any 
improvements I could ever achieve by trying to get a signal enhancement 
from two Beverages pointed in the same direction.  Both units do a great 
job of nulling a AM station on the expansion band right off the  front 
end of both antennas almost down to the noise.  But with the two units 
in the null and the phase switched reversed I was expecting an 
enhancement in that direction but either Beverage produced higher signal 
level when the unit is by-pass by turning it off or with either antenna 
hooked directly to the receiver.

Also my two Beverages that I am trying to phase are end to end. Both are 
600' long and pointing west.  The first one ends where the other begins 
with a spacing of 3 feet and with separate ground rods.  I have seen 
plots, models, and gain figures for broadside or side by side phasing of 
Beverages but have not seen anything on end to end attempts.  Maybe this 
does not work to any advantage. Right now the only thing I have noticed 
is the increase noise floor when the unit is turned on and the ability 
to null stations from the front, both traits are not needed nor desired.

Any suggestions on this would be appreciated.

Herb Schoenbohm, KV4FZ