Towertalk
[Top] [All Lists]

[TowerTalk] Adding 12 Meters to C4

To: <towertalk@contesting.com>
Subject: [TowerTalk] Adding 12 Meters to C4
From: ronc@sonic.net (Ron Castro)
Date: Sun, 24 Jan 1999 09:40:22 -0800
That could be the source of the higher than normal SWR on 12.  The factory
specs are for "~3.2" with 100 feet of RG-213, although I run 70' of RG-213,
connected to 50' of 7/8" Heliax and get around 5:1.  I measured the SWR with
a Bird 43, and confirmed with an MFJ 259 which shows R=17 ohms.
Fortunately, the length of coax causes the SWR meter on the linear to read
about 1.5:1 on both 12 and 17.  Readings and bandwidth on 40, 20, 15 and 10
are almost exactly what the factory specifies, if not maybe a bit better.

Maybe I should leave well enough alone!

Ron
N6AHA
-----Original Message-----
From: Pete Smith <n4zr@contesting.com>
To: Ron Castro <ronc@sonic.net>
To: <towertalk@contesting.com>
Date: Sunday, January 24, 1999 7:57 AM
Subject: Re: [TowerTalk] Adding 12 Meters to C4


>At 12:14 PM 1/23/99 -0800, you wrote:
>>My SWR runs around 5:1 on 12, so the losses are substantial.  Since I have
>>an RCS-8V remote coax switch with two unused ports, I was thinking about
>>maybe a vertical dipole off the boom, or something else horizontal, or in
a
>>quad configuration mounted on the boom.  Any thoughts?
>
>That's distinctly a non-standard SWR on 12!  Haver you considered the
>possibility that you are getting severe interaction with the 80-meter short
>dipole at only 3-foot spacing.  12 meters is the 7th harmonic of the bottom
>end of 80, so it's possible your C-4 is seeing the dipole as a
>low-impedance load nearby.
>
>I would not do anything on or near the boom of the C-4 -- within 6 feet or
>so -- because you're far more likely to mess it up than you are to come out
>with an antenna for 12 that will work well.  with my kind of bad luck, you
>would wind up with a messed up C-4 AND no performance on 12.
>
>73, Pete Smith N4ZR
>n4zr@contesting.com
>
>Loud is.
>


--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm


<Prev in Thread] Current Thread [Next in Thread>