I was reading in ON4UNs book, a section about Beverage antennas and decided to
do some checking on mine, which is celebrating its ten year anniversary this
month.
Mine is 575 feet long, 6 feet high, with sloping ends, oriented NE.
Termination is 500 ohms into a ground rod. Feedpoint also has a single ground
rod to which is attached a potted matching transformer I got at a hamfest and
supposedly designed for this purpose. Feedline is 150 ft of RG8X which is not
grounded at the antenna but just lays on the ground in the woods. Now, this
is my first and only Beverage and there are times when I am literally amazed
at what it can do. It pulled the 3B7 out of the noise and made him armchair
copy on 80 meters when he was simply not there through the noise on the 80 m
dipole. Now I see why some times there were no stations calling him, and how
I was able to get through. I play with it on the BC band to test if it is
really directional. I use my 80 meter dipole as a reference. For example
during the day, here in NJ WBZ in Boston is nearly inaudible on the dipole but
Q5 on the Beverage. The opposite is true for KDKA in Pittsburgh, so I know it
is directional, just don't know if it could work better.

In the book they talk about how it is best if the transformer has an isolated
winding for the 50 ohm input, rather than a bifilar wound one in which there
is dc continuity between all windings. I checked mine and it does have such
continuity. So I may be replacing it with a homebrew one shortly, maybe after
I get some comments from users of this newsgroup.

Also the article warned of the effect of common mode currents on the shield of
the coax degrading the pattern of the antenna so I did a test to see if mine
was infected. It involves simply disconnecting the feedline and shorting the
end, then checking to see if there are signals to be heard. On mine I did not
hear any signals on any ham band, so went to the BC band where I heard a
couple signals. One is a broadcaster about ten miles from here. It was
audible although the S meter didn't budge. Switched to an 80 meter dipole and
it was 20 over 9. So it appears to me that my feedline is quite good, and not
picking up much common mode currents, but that is as far as I have gone. I
haven't installed any choke nor grounded the feedline out in the vicinity of
the Beverage yet. Any opinion, if I would see any difference by putting ina
common mode choke there or replacing the transformer?

Rick K2XT