Jimmy Sullivan W7EJ (SK) had a rotary dipole up for 160 meters at his CN2R
station. You can still see the antenna as his CN2R site is still up. It came
down in a wind storm in 2009, and I have no real knowledge of how well it
worked but one might contact Dick W7ZR for information as he did some
contesting from there. Also Jimmy's logs are still on site as well. A brief
look showed it worked pretty well. Morocco is about 32 degrees North. YMMV
Lee K7TJR
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Jim Thomson
Sent: Saturday, March 31, 2018 10:15 AM
To: topband@contesting.com
Subject: Re: Topband: 160m polarization and elevation angles
Date: Sat, 31 Mar 2018 23:15:00 +0800
From: "Steve Ireland" <vk6vz@arach.net.au>
To: <topband@contesting.com>
Subject: Re: Topband: 160m polarisation and elevation angles
<Equally as Tom W8JI found that his dipole at 300?' feet high (to quote Guy
K2AV) ?would never beat a commercial-AM-BC-quality vertical and radial field,
and only infrequently would equal it?, Mike VK6HD spent at least a year making
A/B comparisons between an inverted vee <dipole (at 90 feet) and a quarter-wave
inverted-L with a 85? vertical section over 132 x 132? radials and found that
mostly the inverted vee dipole was ?'2 ?S? points better than the inverted L on
both receive and transmit.
<Steve, VK6VZ (licensed as G3ZZD in 1971)
## W8JI never had a dipole up 300 ft. He had an inverted VEE up 300
ft. I believe the enclosed angle was far less than 90 degrees.
You require 2 x 300 ft towers to string up a 160m dipole at a height of 300
ft. W8JI only had 1 x 300 ft tower at the time.
Tom, N6BT is adamant that a rotary dipole will outperform an inverted vee
by 6 db, with the apex of the Vee at the same height as the rotary dipole.
N6BT also claimed the rotary dipole would have a 14 db FS.... on DX signals.
## Years ago, I heard these 2 fellows on from Oregon. One of them had up his
new F12 160m rotary dipole, mounted on top of his 120 ft tower.
This 160m rotary dipole was aprx 102 ft long, and used LL wires both
above..and below the main trunk section. The fellow was using a MFJ-259
at the time, and those things wont work below 1800 khz. The rotary dipole
was resonant below 1800 khz. They finally got it sorted out..and resonated
it
at the low end of 160m band. 2:1 SWR BW was aprx 18 khz. IE: + /- 9
khz.. Relays have to be used to switch band segments about.
The very 1st DX station he worked was a 4X4 on CW..... go figure. Trying
to work EU from the west coast on 160M is a tough nut to crack.
## If using an inverted vee..and say oriented N-S..... then move the legs so
they are now E-W, I never saw any difference, minor at best, but that was on
80m,
and also 40m..... and in both cases, the re-orientation of the legs was done
fairly quickly. I believe the baluns I used at the time were flaky at best...
BN-86 junk.
## Other than the fellow in ORE, I never heard about anybody else using a
loaded rotary dipole on 160m. I have heard several rotary dipoles on both 80m
and also 40m.
The 80m rotary dipoles that I have heard on the air had pretty substantial
signals if oriented broadside in my direction. When the bands were lousy, and
signals were weak, the
fellows with the 80m rotary dipoles were way ahead of the fellows with the
inverted vees. I never did find out what the RX noise level was like with
the 160m rotary dipole
in Ore.
Jim VE7RF
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