Which EF180? 30m is so narrow, and most EF180's so long it should work
on all of 30m just by tossing the LL wires and shortening it.
For my EF180C (86' tip to tip) for 80m, I removed the LL wires and
installed a Tornado variable L center coil, replaced many loose element
rivets with thru bolts, did a Yagi-Mech analysis and sleeved where it
was going to fail at 65mph, replaced the crappy ABS center insulator
with machined to fit split colored nylon, sleeved the center with FR4
rod, and installed Phillystran guys (4) to the former LL wire attach
points to a stub mast and 6' cross arm 6' above the boom mounting plate
(made a new HD one also).
Its now a 85 mph design without the element guys and so far so good at
102' high. More than full band coverage.
It's now been up 4 years, so far so good mechanically but do have a
problem with the turns counter reed switch inside the Tornado. Haven't
dug into this deeply yet. Using the MFJ1924 manual screwdriver driver
with the 10 presets at 50KHz steps (it may be the problem with counting
turns). Something bad happened when I went QRO way off tuned
frequency. The 2:1 bw is about 75KHz.
If it has to come down for a reed switch fix, the plan is to reduce the
Tornado L by placing some JKantenna plagerized high q coils just inside
the element guy points. Then I would probably add a third element guy
downward to the mast to prevent updraft failure per Dave Leeson's
recommendation in his book. btw it is mounted above Dave's 40m Moxon
scratch build design.
Grant KZ1W
On 1/4/2016 9:59 AM, Wayne Kline wrote:
All this great conversation on the evolution of the F12 loading wires to
then loading coils and there
development . Got me thinking about my Summer 16 project. I have a F 12 EF180 rotation dipole antenna
Having a 4 sq and HIGH dipole , I hope to modify it to 30 meters !!
I am not sure if Tom ever made a 30 meter rotating dipole but if he did again I assume it's loading
configuration is along the linear loading wire design .
Might try to adapt the lumped inductor to the transition ? thoughts ?
Wayne W3EA
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