On 11/12/2017 2:22 PM, Jim Brown wrote:
On 11/12/2017 1:49 PM, Bob K6UJ wrote:
What I did was make sure
the driver tube was well lubed with Penetrox and slid it out in 1/2 "
increments tillit got down where it was good down in the CW end of
the band
Of course. But the tricky part is being able to rig the antenna so
that SWR can be measured at sufficient height to remove ground
influence on the tuning AND the so that it can easily lower it for
adjustments. Or access the adjustments from a tall A-frame ladder
while it's in the air. While adjusting a very different 4-el for 10M,
I found that the frequency of lowest SWR went DOWN as I raised the
antenna, contrary to what usually happens with a simpler antenna like
a dipole.
A rigging method we often use for portable operations like CQP, 7QP,
and FD uses the 4-ft 2-in o.d. surplus military mast sections in
combination with a tripod base fitting. If the "legs" are two elements
tall, additional mast sections can be pushed up through the center of
the tripod fitting. We use this to get a C3SS up 20-25 ft. We first
learned of this method from a talk that K7JA did at Visalia several
years ago.
73, Jim K9YC
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