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@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of Rex Lint
> Sent: Wednesday, December 23, 2009 2:01 PM
> To: 'bob finger'; Brahmangou@aol.com
> Cc: towertalk@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@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of bob finger
> Sent: Wednesday, December 23, 2009 6:10 AM
> To: Brahmangou@aol.com
> Cc: towertalk@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@GOEASTON.NET
>
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