Jake:
If it's for Field Day only, then forget about the expensive balun. For
a single-band loop, my suggestion would be to use a 1/4WL piece of 72 Ohm
coax (take VF into consideration when calculating 1/4 WL figure) as an
impedance transformer between the nominal 100 Ohms of the loop feedpoint and
50 Ohm RG-8 coax to the rig. (72 Ohms = sqrt(100 Ohms X 50 Ohms.)) If you
want a balun, roll the 1/4 WL coax around a 6 inch paint can for a dozen
turns and use cable ties to hold its solenoidal shape without the can. If
you're running QRO, then use RG-6 rather than RG-59 for the transformer.
73 de
Gene Smar AD3F
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of
jcjacobsen@q.com
Sent: Saturday, May 20, 2017 5:55 PM
To: topband <topband@contesting.com>
Subject: Re: Topband: Loop query
How do Top Banders,
I've got a "theory" question for the collective group.
Think Field Day. Full wave loop on 75/80 meters. Coax fed with a 2:1 balun.
(I know, use ladder line and a Match Box). Is it usable if you use ladder
line down to near ground level into the balun, and coax from there? OR
does/should the balun be up in the air at the loop itself?? We're thinking
put the balun down near ground so the weight isn't up in the air.. Remember,
field day and temp install.
What say you all??
73
K9WN Jake
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