[Elecraft] KX3 and KPA1500 compatibility

Jim Brown jim at audiosystemsgroup.com
Tue Mar 7 04:56:34 EST 2023


On 3/6/2023 2:08 PM, Jim Brown wrote:
> Most (but not all) verticals need radials to transmit a decent signal. A 
> vertical that needs radials is a lousy TX antenna without them.

To expand on this -- the BTV-series, the Butternut and a few others use 
various forms of traps and resonators that essentially function as a 
quarter-wave (or odd multiple of quarter-waves) verticals. The DO need 
radials. Length on the ground is not critical, and more is better.

The Hy-Gain AV-series, and another similar design by another designer 
(all currently mfd by MFJ) are loaded, center-fed half-wave antennas, 
and do NOT need radials (and work best without them). I could give you 
family name of the other design (also mfd by MFJ), but my copy of the 
N0AX/K7LXC review of them is currently out on loan to another ham. My 
81-year-old brain can only remember so many details.

N6BT (original Force 12 designer, VERY sharp engineer), designed a lot 
of excellent center-fed loaded designs for that company, which he owned, 
and brands after he sold Force 12. Tom is a far better designer than 
businessman, and I love him dearly. :) His self-published "Array Of 
Light" is a GREAT education, and includes many of his designs. 
N0AX/K7LXC very disciplined tests of both verticals and tri-banders 
showed Tom's designs to be leading both packs! Our 7QP/CQP/FD team owns 
three of his C3SS Yagis. Tom is also very sharing of what he has 
learned, zero ego, and I've learned a LOT from him. His measurements 
(using drones) on the effect of terrain (above a dropoff in the 
direction of DX) on the performance of verticals, first presented at 
Pacificon about six years ago, was ground-breaking!

73, Jim K9YC


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