Topband: Noise and reception

[k3ky@erols.com]

I have been using the K6STI horizontal loop design described here
for several years now. I am very happy with mine, built switchable
to cover 75, 80, and 160. STI comments that the output will be
lower if the matching circuit is not peaked up, and I suspect this
might be tha case here- the S/N *ratio* would stay precisely the
same, however, whether or not the tuning is right. Although I have
successfully used mine without a preamp, one is highly
recommended! BTW this antenna is an omni-directional signal
inhaler- it theoretically should produce no improvement whatever
in S/N if the predominate noise source is lightning static.

I have 4 basic low noise rx-only antennas here presently- a 225ft
'shorty' terminated Beverage, the K6STI horizontal loop, a K9AY,
and a Flag. All are pointed at Europe except for the K9AY which
listens to the west. I have been very happy with all, although at
times one or more of them are virtually deaf. At other times, they
deliver surprisingly high signal levels (no preamp). My best 
performer, on average, is the shorty Beverage. The K6STI loop
is a close second, with the K9AY and Flag both delivering good
performance, too. Each has its moments. All I can say is that I am
*very* happy with the K6STI loop, and have repaired it twice
after big tree branches fell on it and broke wires. It is definitely a
keeper. Among all 4 types, this loop is the only one that is
designed to *reject* vertically-polarized noise and respond only
to Horizontally-polarized signals ( at fairly low elevation angles).
Most man-made noise is vertically polarized *unless* it is very
close to the antenna, in which case all bets are off! Sometimes
this loop is deaf, other times its performance is just short of
amazing. I always recommend that any top band operators keep
a small arsenal of *different* types because conditions are so
variable. Of course, if you have a lot of room like Tom, longer
Beverages are the way to go. He seems to like them best in the 
500-800ft lengths. I have only very brief personal experience
with them at other hams' stations, but it was enough to show me
that, if I had the room, I would probably have mostly Beverages.

http://www.angelfire.com/md/k3ky/page45.html
(my web page about the K6STI loop)

The K6STI loop may or may not cut it for west coast types on
top band- for an east coast guy like me, it plays very well for Eu
and SA. Recommended!  73, David K3KY

On 11 Feb 2002 at 21:59, Donald Chester wrote:

> This summer I constructed a small square horizontal receiving loop fed
> diagonally at each corner  with open wire line, as described in the
> two articale in Sept 95 QST.  Although I occasionally get good results
> with it, for the most part this antenna was a waste of time, usually
> giving little noise improvement over  my rotatable loop, while
> delivering so little signal that internal receiver noise becomes a
> problem.   Has anyone had any kind of good results with one of these
> antennas?  So far I have found no  discussion in the archives.  Have
> not yet tried flag, pennant or ewe.