Good advice, Steve. Some form of capacitive top loading (top hat
or even a single horizontal wire) will raise the feedpoint R too.
Mike, W4EF..........................
----- Original Message -----
From: "Steve N4LQ" <n4lq@iglou.com>
To: <tentec@contesting.com>
Sent: Sunday, November 14, 2004 9:54 AM
Subject: Re: [TenTec] Hi power Ten Tec ant tuner swr drift?
> The feed impedance of that short antenna is much too low. You are going to
> melt down your tuner. Any tuner will get hot and consume a large
percentage
> of your RF power when attempting to match such a low Z. If you are feeding
> it through the balun, you are making the situation even worse due to the
4:1
> ratio. It may be transforming 10 ohms into about 3 ohms! Try bypassing the
> balun and feeding it like an unbalanced antenna ( it is unbalanced
anyway).
> Another cure is to raise the Z of the antenna with a loading coil around
> midpoint in the vertical.
> Steve N4LQ
> ----- Original Message -----
> From: "denton" <denton@oregontrail.net>
> To: "Tentec Reflector" <tentec@contesting.com>
> Sent: Sunday, November 14, 2004 11:43 AM
> Subject: [TenTec] Hi power Ten Tec ant tuner swr drift?
>
>
> Hi all...
> I have recently purchased an old Ten Tec L network ant tuner..the one that
> was in kit form many years ago.
> I have noticed that when feeding it to a 22 ft elevated ground plane on 80
> meters (yeah I know, really a mismatch) via 450 ohm twin lead that the swr
> will drift on 80 meters and the 2 kv ceramic caps on the cap switch will
get
> really hot...
> Will switching the caps to transmitting micas alliviate the problem??
> Bad switch??
> 80 meters on this particular antenna apparently is the only band this
occurs
> with this transmatch...my 238A does not exhibit this little problem when
> feeding the same antenna.
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