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Re: [TowerTalk] Problem With Force12 C31XR

To: 'Alfredo Vélez WP3C' <>, <>
Subject: Re: [TowerTalk] Problem With Force12 C31XR
From: "Tod -MN" <>
Date: Sun, 30 May 2010 20:58:28 -0600
List-post: <">>
I found that my C31XR was also resonant at 21.0 MHz or so. In the end I
adjusted the length of the driven element -- made it shorter by about the
amount the last tip extended from the DE.  It was still a bit low and I will
be adjusting it again in July when I work on the Idaho Antennas. I also
found that I needed to make the inductance at the center of the 15m driven
element almost zero to get close to the proper feed point impedance. 

I am guessing that there may be some subtle production changes which
occurred when the new Force12 manufacturing was started up. Eventually the
manufacturing problems, if any, will be resolved I am sure.

Tod, K0TO

> -----Original Message-----
> From: 
> [] On Behalf Of 
> Alfredo Vélez WP3C
> Sent: Sunday, May 30, 2010 6:48 PM
> To:
> Subject: [TowerTalk] Problem With Force12 C31XR
> HI
> I installed the Force12 C31XR at 75 feet tall and I have a 
> problem in 15M, it resounds in 20.000Mhz and in 21.000Mhz 
> have 2:5; when I take out one jumper that connects the 
> 10Mdriver with the 20M it downs the SWR in 21.000Mhz to 1:7 
> and levels up the SWR in 20M. I don?t know if those jumpers 
> made the driver longer and that?s why resounds in the 
> 20.000Mhz. I don?t know what to do because it is by the 
> manual. Any help will be well received!
> Here is a picture:
> Alfredo Vélez WP3C/NP4DX
> Skype:
> e-mail:
> Web:
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