[TowerTalk] Making an 80 meter vertical from Rohn 25

[Les Kalmus]

On the other hand, for the past 4 years I have two variables in a small 
tuning network in a 12" x 12" weather tight PVC box from HD.
I drilled several 1/16" holes in the bottom and have not had a moisture 
problem since.
My variables are still like new (err... used actually).
I would love to motorize them but have never found motors I could use.

Les W2LK

Chet wrote:
> Hi Rex,
>
> My $15 variable worked "as advertised" just like you have suggested. Even
> though I had mine in a sealed container, I had rust on all the plates in 
> About 3 months. Shaft started to be hard to turn in 6 months. I suppose they
> Exist but I have never seen a motor attached to the $15 dollar version. I
> Replaced mine with a Jennings VVC and put it in the same
> Container.  It still as bright and shiney as it was the day I put it in
> there  5 years ago. In addition,  With the motorized VVC I can tune my VVC
> remotely From the shack. This is a real plus during the 160M contests when
> you need to go up to 1900 or above.  If you were to get 6 months apiece on
> the $15 Caps that would be two per year and for me that would already have
> Come to 150 bux, I think I am ahead with the VVC. Not to Mention the
> convenience of the remote tuning feature If you  have a bunch of those hefty
> variables, you can certainly use them until they rust out.
>
>
>
> 73
>
> Chet  N4FX
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com] On Behalf Of Rex Lint
> Sent: Wednesday, December 23, 2009 2:01 PM
> To: 'bob finger'; Brahmangou at aol.com
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] Making an 80 meter vertical from Rohn 25
>
> Bob,
>
> I know folks use vacuum variables at the feedpoint of verticals, but I don't
> understand why.  It's a fairly low impedance (and therefore low voltage)
> point, isn't it?  Wouldn't a hefty variable work just as well?  $15 compared
> to $80 or so?
>
> Rex
> K1HI
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com] On Behalf Of bob finger
> Sent: Wednesday, December 23, 2009 6:10 AM
> To: Brahmangou at aol.com
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] Making an 80 meter vertical from Rohn 25
>
> Get hold of a copy of ON4UN's Low Band book.  It is available from ARRL.
> Johns book is considered the bible for low band antennas.  That book will
> tell you that a 12 inch tower will be resonant on 3500 if it is about 64
> feet long, and a tower about 78 feet long feeds easily with some series
> capacitance in the feedpoint. A vacuum variable of about 1000pf should allow
> you to easily tune to any point on the 75/80 band. 
>    All assumes 5 ohms of loss in the radial system. 73 and Merry Christmas
> bob de w9ge
>
>   
>> I'm wanting to put up a full sized 80 meter vertical made from Rohn 25 
>> in my pasture.
>> Marty Haley AB5GU
>>
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>>
>>  
>>
>>     
>
> --
> Bob Finger
> 8511 Swann Haven Road
> Easton MD  21601
> cell 703 408-2176
> e-mail to: Finger at GOEASTON.NET
>
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