[PVRCNC] Anyone use extended double zepps?

[Nathan Moreschi]

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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