Tim,
I am curious, is there any reason why the center tower in that array of
yours could not be shunt-fed? I suppose that might require de-tuning the
tower in order to adjust the parasitic elements, whereas with a base
insulated tower you could just open-circuit the driven elements.
Do you know of anyone who has made this sort of array work with a
shunt-fed tower as the primary support?
73, Mike W4EF............
On 7/19/2026 11:22 PM, Tim Duffy wrote:
Speaking of base fed insulated towers on 160... that happen to be 90 degrees
high (about 120 feet) - by design... I have had this for over 30 years - it
is what I think is the best vertical antenna array for 160 that I have
found. Bandwidth performance is narrow - but it tunes up easy and it really
works. AA1K, VE3EJ, K9CT, W5ZN and NR5M and others all use the K3LR Yagi
vertical design. WA3FET and K3LC worked with me on the early designs.
This is a very effective gain antenna (almost 6 dB) with good front to back
ratio (30 dB and can be used on RX with attn.) is described in editions 3,4
and 5 of the ON4UN Low Band DXing book by ARRL. Only takes a single 120 foot
tower (all tower sections must be Cad welded together). It is a Three
element vertical parasitic beam (shoots in four directions). BUT needs FIVE
radial systems of 1/4 wavelength radials... I use 120 radials per element -
one quarter wavelength long - 130 feet.
The most recent version of this antenna has been updated by work (28 pages)
from Greg, W8WWV here:
https://www.k3lr.com/engineering/160m/K3LR160m2024Revisit.pdf
This is currently what is in use at K3LR. Twice this array/station at K3LR
worked more than one hundred countries in a single CQWW CW weekend on 160
(48 hour contest).
We have just installed a brand new broadcast style radial system (all silver
soldered) for all five vertical elements - this summer of 2026 (old one was
35 years old). Thanks W3YQ for engineering the installed solution.
The performance is spectacular.
73
Tim K3LR
-----Original Message-----
From: Topband [mailto:[email protected]] On
Behalf Of Rob Atkinson via Topband
Sent: Sunday, July 19, 2026 8:29 PM
To:[email protected]
Subject: Re: Topband: The Big Guys
you can have a broadcast tower that's too tall for 160 m. which
results in high angle lobes. For this to work well you need one for a
station that's up near the top of the broadcast band. A good way to
tell is whether or not the tower is lamped. The ground system
certainly helps but a ham can put in a good ground system on his own
monopole. Don't believe that only broadcasters can do this, although
nowadays a lot of radials on 160 costs a lot more than they did 25
years ago. These antennas will likely stink on receive. You'll just
pick up noise. Expect to have to set up some sort of separate receive
arrangement. By the way, there are and have been a few hams with base
fed insulated towers and ground systems on 160. They don't chase DX
or contest so you may not have run across them.
73
Rob
K5UJ
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