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Re: Topband: Fw: 25G insulators

To: <>, "Earl W Cunningham" <>
Subject: Re: Topband: Fw: 25G insulators
From: "Milt Jensen, N5IA" <>
Date: Sat, 30 Aug 2003 06:34:36 -0700
List-post: <>
Good morning Earl and others,

My experience is NOT this result.  I had a full sized 1/4 WL of Rohn 25,
ground mounted and grounded, that I Gamma matched.  2:1 bandwidth was 20
kHz.  I converted the same stick to seried fed by installing the insulators
and immediately the 2:1 bandwidth went to just over 100 kHz.

Performance was equal in both cases, but NOT having to fiddle with the
remote tuning of the Gamma cap was more than worth the effort of installing
the insulators.

The arc gaps across the insulated section is a simple and very effective way
of taking care of the static charges.

End of conversation.  Milt, N5IA

----- Original Message ----- 
From: "Earl W Cunningham" <>
To: <>
Sent: Friday, August 29, 2003 8:20 PM
Subject: Re: Topband: Fw: 25G insulators

> Milt, N5IA wrote:
> "MUCH smaller bandwidth unless you want to do remote >control of the shunt
capacitor.  It is well worth the effort (coin >and sweat) to make the
antenna a true Ground Plane."
> ==========
> Not true if the shunt-fed tower is close to 1/4-wave tall.  The 2:1 SWR
> BW is just as wide as with a 1/4-wave series-fed vertical.

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