Ron,
Opinions are just that. I totally disagree with both Jim and KXBill.
I presently run some 600 foot of home made 4" spaced open wire to my wire
20m yagi, and also to both of my 40m EDZ antennas. I just don't think 600'
of 'black snake' would really be worthwhile? Insertion loss charts still
today shows open wire feed line to be better than anything wrapped in a
black jacket, or any color jacket for that matter.
Most all of the 'no-no's' you read about how you must use or route open
wire, is subject to hearsay. I have seen open wire line buried in a PVC pipe
and run for some 60' with no bad effects. I have seen open wire coiled into
some 20 turns (about a foot in diameter) by a friend and it worked fine for
him.
So my experience is that open wire feed line is only "highly over rated" by
those who do not believe in physics!
What I would try is just adding a random length to what you already have,
and make it long enough to run around the other side of your house until
your construction is completed. FORGET BALUN's!! (If you have a yagi, use a
balun/if you have a dipole forget a balun!) If you can no longer tune your
80m dipole, simply add or subtract (in about quarter-wave lengths) line
until you can again tune your dipole. It works..plus if you add another 100
foot of open wire, you will have increased your line loss by the whopping
sum of almost 0.2dB!
73,
Tom - W4BQF
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Bill Harris
Sent: Monday, September 28, 2009 3:32 PM
To: Jim Brown; TowerTalk
Subject: Re: [TowerTalk] Open wire
Jim is right on...However, if you want to use the antenna on other bands
you're best off using open line.
YMMV
KXBill
--------------------------------------------------
From: "Jim Brown" <jim@audiosystemsgroup.com>
Sent: Monday, September 28, 2009 11:52 AM
To: "TowerTalk" <towertalk@contesting.com>
Subject: Re: [TowerTalk] Open wire
> On Mon, 28 Sep 2009 14:42:11 -0400, w4lde wrote:
>
>>I am feeding a 80 meter center feed with open wire, about 100ft feed-line.
>
> Open wire line is highly over-rated, especially on a resonant antenna. Do
> yourself a favor and buy 100 ft of RG8 or RG11. Now, you can add a coaxial
> ferrite choke at the feedpoint, which will likely make the antenna quieter
> on receive and minimize RF in your shack (and your neighbors homes). The
> loss in 100 ft of RG8 or RG11 is negligible on 80M, even with 5:1
> mismatch,
> which is about as bad as it can get at the band edges. See my tutorial for
> details on the coaxial choke. http://audiosystemsgroup.com/RFI-Ham.pdf
>
> 73,
>
> Jim Brown K9YC
>
>
> _______________________________________________
>
>
>
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>
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