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Re: [TowerTalk] G5RV vs 40M dipole

To: towertalk@contesting.com
Subject: Re: [TowerTalk] G5RV vs 40M dipole
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Sun, 26 Apr 2015 01:46:08 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
I have a 75 Meter fan. Even with a 3' separation at the ends with the top near 90 feet and the lower end nearly in the trees. my neighbor on that side never noticed the "contraption" Compared to thye tower the antennas are almost invisible. Everything is relative.

For the nulti band why not use spreaders to form a triangle at the ends of the higher bands. Even with a 6" separation if under tension they should not have adjacent wires touch. Mine is probably under 50 to 60#. Maybe more. The feed and multi core choke and LMR-400 feed line hang from the center with no noticable sag...So they may be under a bit more tension than I thought. The top end is pulled up via 5/16ths dual core poly rope that goes through a heavy duty pulley near the top of the tower. The rope then comes down the tower and is fastened at about the 8' level. I'll try to explain how I tighten it.

The rope runs inside the tower between several cross braces, I grab the rope between the braces with my left hand. the rope comes out under the lower cross brace. I pull the rope out a foot or so with my left hand., then pull out most of the excess with my right hand. as long as I keep tension on with both hands, the friction helps keep the rope from going back up the tower, so it looks like a seesaw movement between the hands with the left hand moving up the rope and winding the excess around my right. It's easier to demonstrate than explain, but you can really put some tension on with this approach, or I could when my left hand still worked.


I still have the 100' 45G, but currently it only supports the ends of 3 wire antennas.

73

Roger (K8RI)


On 4/25/2015 8:42 PM, Larry Loen wrote:
Try both; experiments are cheap.  You can build both of this for maybe 50
dollars for both of them.  I've never done the G5RV "junior"; results could
be interesting.

I think on the whole the fan dipole will probably outperform the junior,
based on my observations of how the full sized G5RV performs, though.

The main thing with the fan dipole, especially in a one man assemble and
deploy, is to make very sure the wires don't cross.  A modest bit of PVC
pipe at the 10 meter end will ensure this if your neighbors can stand the
"visuals".  Otherwise, it can be tough to avoid at least one "crossover"
near the feed point, which I do not recommend based on my own doleful
experiences.


WO7R

On Sat, Apr 25, 2015 at 5:10 PM, Bry Carling <bcarling@cfl.rr.com> wrote:

I'm not a fan of fan dipoles. G5RV all the way!

Best regards - Brian Carling
AF4K Crystals Co.
117 Sterling Pine St.
Sanford, FL 32773

Tel: +USA 321-262-5471




On Apr 25, 2015, at 5:43 PM, Jim Brown <jim@audiosystemsgroup.com>
wrote:
On Sat,4/25/2015 1:50 PM, Wes Attaway (N5WA) wrote:
Without getting into a never-ending discussion of "which antenna is
best", I would suggest that you consider just dropping 3 or 4 feet of each
end straight down so that the remaining horizontal length will fit in your
available space.
Yes, that's your best option.

If you want more bands, consider building a fan dipole for 20, 30, and
40 and feed it with 50 ohm coax. With a tuner, it will also work on 15M.
See k9yc.com/publish.htm  for ideas. Study Antennas For Limited Space.

73, Jim K9YC
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--

73

Roger (K8RI)


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