Or a couple of relays to select band segment fixed caps. I did that at a
prior QTH on 160 using 24VDC new surplus relays from All Electronics.
Carl
KM1H
----- Original Message -----
From: <donovanf@starpower.net>
To: <topband@contesting.com>
Sent: Thursday, September 01, 2011 11:58 AM
Subject: Re: Topband: Antenna Matching Question
> Phil,
>
> How about using a selsyn to turn your capacitor? It will require some RF
> isolation, but that shouldn't be hard.
>
> 73
> Frank
> W3LPL
>
> ---- Original message ----
>>Date: Thu, 1 Sep 2011 08:57:33 -0500
>>From: "Phil Clements" <philclements@centurylink.net>
>>Subject: Topband: Antenna Matching Question
>>To: <topband@contesting.com>
>>
>>Much has been written about matching 160 meter shortened vertical
>>antennas,
>>but very little about 160 meter antennas that are too long. There were two
>>great articles in the old "Communications Quarterly" in 1998 about
>>elevated
>>ground planes, but I have lost them over the years. My current system was
>>built from these articles.
>>
>>
>>
>>The system here is a 195 foot Rohn 25 tower, with insulators at the 60
>>foot
>>level. The five sets of guy wires are all insulated from the tower, and
>>additional insulators along their length to be invisible to 160 meter RF.
>>The guys at the 60 foot level, just below the tower insulators are
>>utilized
>>as the radials that form the ground plane. They are 110 electrical degrees
>>long. The system resonates at 1510 KHz, requiring a capacitor connected
>>across the feed point. 600 pf brings the system into resonance @ 1830 KHz.
>>
>>
>>
>>There will soon come a day when I will not be able to climb to the 60 foot
>>level to adjust the matching capacitor when needed. The question is: Can I
>>place the capacitor at ground level, connected to the original feed point
>>via coax or open-wire line? Will this 60 foot line radiate? I do not want
>>to
>>upset the radiation pattern of the system. I tried a motorized vacuum
>>variable several years ago, but it was a high maintenance item due to
>>exposure to the elements.
>>
>>
>>
>>I am open to all suggestions; perhaps some brand new ideas will surface
>>from
>>all the expertise on this reflector! After 57 years on the air, I am
>>still
>>learning, and trying to make improvements here!
>>
>>
>>
>>Thanks in advance for any/all comments.
>>
>>
>>
>>(((73)))
>>
>>Phil, K5PC
>>
>>_______________________________________________
>>UR RST IS ... ... ..9 QSB QSB - hw? BK
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
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_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
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