Topband: Dipole/remote tuner

[Dino Darling]

A dipole we've used successfully at Field Day is actually a 40-meter, 2 element wire beam hanging from an 18' boom.

The driven element is a simple dipole fed with ladder line down to a remote tuner (in our case, a classic Johnson KW Matchbox). The ladder line is just long enough to reach the ground where the tuner sits on a milk crate and inside a trash bag. Then a random length of coax runs from the tuner to the radio tent. We tune the tuner at the tuner using a simple analyzer.

Since we run a frequency rather than searching and pouncing, this rough set up works great. If we ran a remote autotuner instead, we could move across the entire band.

This set up is not as elegant or efficient as Jim's by any means, but its quick and simple and works.

Dino - KX6D
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From: Topband <topband-bounces+dino=kx6d.com at contesting.com> on behalf of Jim Brown <jim at audiosystemsgroup.com>
Sent: Thursday, November 17, 2022 7:43:07 PM
To: topband at contesting.com <topband at contesting.com>
Subject: Re: Topband: Dipole/remote tuner

On 11/17/2022 7:22 PM, john at kk9a.com wrote:
> You can significantly widen the SWR bandwidth that your radio sees on 80m by
> using a coax match. Connect your dipole to a 1/2 WL multiple of 50 ohm coax
> and then add a 1/4 WL section of 75 ohm coax. Of course this does not change
> the actual antenna's SWR but neither would a remote tuner.

Yes. There's a development of this concept on my website, where the
matching method is used as an example in a tutorial on using SimSmith to
design antenna matching networks.

http://k9yc.com/PacificonSmithChart.pdf

When I was introduced to the concept by local contesters, they credited
it to Dave Leeson, W6NL. When asked about it, he said the idea was much
older than he was.

73, Jim K9YC


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