Dick,
Quarter wave slopers just don't work well unless there is top loading -
at least that has been my experience. If I had a 60 foot tower I would
shunt feed it and use it as a vertical. You will be quite pleased with
the way it will work with a reasonable ground system under it. I will
work fine with a small tribander for 80 and 160 so your ground system
will be good for the future.
To answer your question, I would be prepared to make it a LOT longer
than you think it should be. I would start out with about 85 feet of
wire and fold it back a couple feet at a time to get it in the band
where you can then finalize it. I think you would be better off with an
Inverted V at 60 feet and then shunt feed the tower after you get the
tribander up.
Stan, K5GO
----- Original Message -----
From: <RLVZ@aol.com>
To: <towertalk@contesting.com>
Sent: Wednesday, December 29, 2010 5:59 PM
Subject: [TowerTalk] Length of Sloper?
> Hi Guys,
>
> I'm installing an 80-meter Sloper on a self-supporting 60' tower.
> (no
> guys) I don't have a MFJ-259 or other antenna bridge with me so I'd
> appreciate your thoughts to help get me in the ballpark. The
> 80-meter Sloper will
> attach to the tower at the 55' level. Currently there are no other
> antennas
> on the 60' tower. A couple questions:
>
> 1) With no other antennas on the 60' tower, do you think the length of
> the
> Sloper wire will be close to the formula 234/freq? Or do you think
> the
> Sloper will wind up needing to be longer or shorter than 234/freq?
>
> 2) The once I get the Sloper tuned for minimum SWR on 80-meters, if I
> later
> add a Tribander to the top of the tower I'll no doubt need to re-tune
> the
> Sloper, but do you think the Sloper will need to be shortened or
> lengthened after the Yagi is added?
>
> Thanks & 73,
>
> Dick- K9OM
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