[PVRCNC] Anyone use extended double zepps?

[Guy Olinger K2AV]

This is not unlike the 28' on a side doublet that we (including Nate)
string up at IOTA out on Core banks every year.  Window line is a little
lossy, but we have to use something like that out there.  Open wire line is
better, to as close to the operating position as possible.  Balun made for
open wire, to six to eight feet of really good coax (I like RG393,
silver-teflon) to the tuner.

On Mon, Jan 30, 2012 at 4:07 PM, Nathan Moreschi <n4ydu at yahoo.com> wrote:

> Will,
>
> Eliminating the 25 feet of coax will make a huge improvement - potentially
> in the 10 to 20 db range depending on the band.  If anything, I would
> shorten the antenna a little bit for the high bands. 23 feet per side is an
> EDZ on 12M but 40M performance drops quite a bit at that length. You could
> go to 28 feet per side which is an EDZ for 15 and that will perform fine on
> 15 and below and probably OK on 12 or even 10. I use a similar antenna for
> an alternate antenna in contests with good results.
>
> I think extending it would be great for the low bands and could make a
> killer antenna there (between your towers) but it would be hard to predict
> the performance on the high bands. But with experimenting you'll probably
> find some spots where it works quite well. I find it to be a big juggling
> act when it comes to playing with the lengths and relating it to all-band
> performance.
>
> I've done a lot of experimenting with antennas like this - most of my
> reasoning is based on real use rather than modeling.
>
> 73,
>
> Nate/N4YDU
> -----Original Message-----
> From: Roberts, Will
> Sent: Monday, January 30, 2012 2:53 PM
> To: pvrcnc at mailman.qth.net
> Subject: [PVRCNC] Anyone use extended double zepps?
>
> I use a 32' per side doublet as a 30/17/12 meter antenna, and it can also
> double as an extra  "utility" antenna for the contesting bands if an extra
> antenna is needed. It is fed with ~60' of ladder line, a 4:1 balun and ~25
> of RG213 coax into a K3 with tuner. It works pretty well and most of the
> time I use it with 5 to 100 watts chasing band countries. I want to try to
> improve on this antenna by replacing the outside balun and bringing the
> ladder line in the shack. I'm sure the SWR on that 25' of coax is very high
> and is lossy. I can also eliminate the need for the balun and the K3 tuner
> by using an external tuner with a built-in balun. I am also wondering if
> changing the lengths to make it longer would help performance? It actually
> works worse on 12/15m. I'm attributing this to the coax loss, although it
> could be directivity to places I don't need it. The antenna is oriented
> N/S.
> I could easily double the length and still hang it between towers as a flat
> top. Thoughts??
>
>
> Tnx,
> Will AA4NC
>
>
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