A few individuals directed questions towards me, in my
last posting regarding my delta loops. So I thought that
I'd just put out a general "to all" posting, in case there were
others who might be interested in any of this.
The QST article that I used in the construction of my delta
loops is found in the Oct. 1984 issue, beginning on page
24. The article is titled "The Full Wave Delta Loop At
Low Height" and I constructed my delta loops exactly
as they were described in that article.
My 80 meter delta loop has the apex supported by a corner
of a flat plate on top of a 90' tower. The bottom of the
loop is about 15' above the ground and is "pulled out"
away from the house, to get it away from the tower, the
metal gutters on the house and also a large bush on one
of the corners of the house.
My 160 meter loop likewise has the apex supported by a
corner of a flat plate on top of a 136' tower. The bottom
of the loop is about 9' above the ground and due to the
long bottom (horizontal) span, is supported in a couple of
places to minimize sag.
The 80 meter loop is made from #12 enameled copper
wire (obsolete magnet wire!) and the 160 meter loop is
made from #16 copperweld wire. For the 75 ohm
matching sections, I had originally used "flexible type"
RG-59/U coax, which is nothing more than the normal
RG-59/U coax with a stranded copper center conductor,
instead of the usual solid conductor RG-59/U coax.
After using these loops for a number of years, I thought
that it might be a good idea to "upgrade" the 75-ohm
matching section to the heavier RG-11/U (same physical
size as RG-8/U coax) because I ran a kilowatt linear amp
in contests on the low bands and I didn't want to run the
risk of the smaller coax breaking down. When I replaced
the RG-59/U matching sections with the larger RG-11/U
coax, I carefully inspected the RG-59/U coax and could
not see any part of either coax with any physical damage.
I'm sure that my delta loops cannot compare to the per-
formance of "four square" arrays and other special re-
ceiving antennas, but for their simplicity, my delta loops
have served me very well over the years. A few years
ago, I bought a used M2 80 meter rotatable dipole and
had hopes of mounting it on top of my 136' high Rohn
45 tower. I have not yet put it up and am very hesitant
to do so because I am afraid that it will not appreciably
"hear better" than my 80 meter delta loop already does.
Anyway, that's the situation at Radio Free Roscoe (IL),
in case anyone is interested in any of these details. Good
DX and CU on the bands...BTW, I operate about 90%CW, so you'll most likely hear
me chasing DX in the CW
sub-bands...73 de Brad, N9EN (ex-KA9LTR)...
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