I haven't looked up Hawker's comments yet, but another scheme is to wire
up a switch to disconnect the coil and extension wire for the higher
bands. I think I've seen a commercial product for that. Might require
making the basic antenna a folded dipole with bypassed relay coils being
the shorts at the ends so you insert series capacitors at the balun and
with a couple RF chokes apply DC to close the relays hanging at the ends
of the original center section.
73, Jerry, K0CQ
On 4/8/2011 9:56 PM, Art Trampler wrote:
In the old vernacular--cool idea.
Since the motivation was to get coverage on 80 and better coverage on other
bands...the 160 was more of a, "What's going on here?" question. However, I
like this thought on this one.
Art
-----Original Message-----
From: tentec-bounces@contesting.com [mailto:tentec-bounces@contesting.com]
On Behalf Of Dr. Gerald N. Johnson
Sent: Friday, April 08, 2011 4:25 PM
To: tentec@contesting.com
Subject: Re: [TenTec] SLIGHTLY OT
Perhaps it would be more useful to connect the ends through coils that would
bring the antenna nearly to resonance on 160 and by their choke (neglecting
distributed C to make into traps which may not be a perfect
assumption) effect disconnecting the added wire on the higher bands. The
choke will be more effective on 80 through 30 than 20 through 10 meters
because the distributed will likely make the choke series resonant somewhere
in that range and above that resonance it looks capacitive.
I'm sure I've read about such chokes in Pat Hawker's antenna topics volume.
73, Jerry, K0CQ
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