On 10/28/2025 7:15 AM, john@kk9a.com wrote:
Back when N6BT owned Force12 they manufactured Sigma vertical
dipoles. It
was a sideways H shape fed in the middle and it had handmade wire
inductors
to reduce the length. I always thought that was a pretty good
antenna for
its size and ease of installation.
Tom has done a lot with loaded vertical dipoles. It's a very
interesting concept. W6GJB has built some that we've jointly designed,
based on his ideas. One of them, for 80M CQP and 7QP county
expeditions, worked quite well, but got destroyed in the wind because
the Spiderbeam pole we used wasn't built the way the vendor said it
was, and didn't have the mechanical strength they claimed. Glen is a
fine mechanical engineer, retired from the space program.
In extensive RBN testing, it outperformed an inverted vee with an apex
at 50 ft by more than 6 dB.
73, Jim K9YC
My 160M TX antenna is a center fed vertical dipole, more of a capital I
than a sideways H because I have a couple tall towers to suspend it
from. But it works so well that if the towers were shorter I would use
the sideways H version without hesitation. I've got a CM choke at the
feedpoint. The 'bottom' hat is ~15' off the ground.
-Steve K8LX
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