Topband: RX Antenna nul discovered

[Herbert Schoenbohm]

Bob, VE3OSZ wrote:


 "..... for the past several years I have had real problems trying to work
Herb, KV4FZ. I call and call without success. Eventually Herb may hear  me
but with obvious difficulty at his end. I had the same experience in the  CQ
160 with KP2ZZ at Herb's station. I finally worked him but it took many
many calls....". I have come to the conclusion that Herb's Beverages have a
null in my direction..."    Well Bob is absolutely right!.....and...

Thanks to Bob's observation and his willingness to express them I indeed I
found a real null with my 550 foot beverages into Eastern Canada and the
Maritimes.  I have had some clues to this in the past but Bob's remarks
convinced me to try and  prove it.  For the ARRL SSB I put together a K6SE
design Delta Pennant (FO0AAA) and aimed it straight north.  During the
contest I was able to hear many stations that were not audible on either the
WNW Beverage and the ENE Beverage. I always thought the nose was broad but
in my case there indeed was a deep hole straight north from my QTH.since all
of my Beverages are in a pasture south of my QTH my ability to shoot
straight north was limited.   The simple Pennant made from cat 5 cable w/o a
preamp made a believer out of me that I was essentially deaf in one regional
area due to the orientation of my Beverages.

I have tested the North Pennant against the WNW Beverage with nearly 100
stations across NA and generalizations are offered:

Eastern Canada, Maritimes the North pennant always beats the WNW Beverage by
1 to 3 s units.
East coast in general the results vary with the North Pennant favoring the
Ivy league states.
East Coast from GA south and westward to the West Coast the Beverage always
better by several s units.
I think these results are as they should be. I will keep running the tests
for several months to make sure that band conditions are reduced as a
factor.

The real proof, IMHO, was listening to Jack VE1ZZ who now has the thundering
consistent signal of years past at my QTH. In recent years I was saying to
myself how can a station with such a puny signal work all this DX. I found
all of this was due was due to the selection andorientation of my battery of
RX antennas. I know, Beverages are the DX-ers RX antennas of choice but the
mistake, like I made, in relying to much on them should be noted. The
patterns may not be as broad as formerly held at least not here.  I now also
make it a habit to switch to the vertical on RX because there are times when
it was the only antenna I could copy stations on even though the QRN was 50
over!  Now  I really need to find out how to effectively reverse the
direction of a Beverage. Removing the termination is not a good option as
the noise floor jumps up.  Additionally I have never read any glowing
reports about a two wire Beverage every working as well as a single wire in
its favored direction.  If they really work I wonder if the same CAT 5 cable
(4 strands north and 4 strands south) or 300 ohm twin lead could be used
rather than a wider spaced two wire setup? I noticed the two wire design
does not use a termination resistor. If that is the case would not the noise
floor increase reduce the actual value of this arrangement?

Comments on these questions would be greatly appreciated.

73

Herb Schoenbohm, KV4FZ