I have Omni 7 and T-T's latest version of their high power antenna tuner
(don't recall model number off hand). Up on the house roof (cedar
shingles) is my old Hy-Gain 40 - 10 meter vertical with two radials for
each band. All of the antenna is above dc ground. At base of vertical
is SO-239 coax connector. This entire antenna looks like a balanced
antenna to me. Why not feed it with ladder line through my tuner? Go
around the SO-239 at the base. As you say, a balanced antenna system is
best using ladder line. So why not do this? I have always wondered
about this.
-------- Original Message --------
Subject: Re: [TenTec] Re. [Ten Tec] Grounds
From: Stuart Rohre <rohre@arlut.utexas.edu>
Date: Wed, January 25, 2012 1:30 pm
To: tentec@contesting.com
Wade probably has some critical resonant length of feedline that feeds
RF back to this station from the antennas when his good earth bonds are
not connected.
In this case, he has done a good job of earthing his station. The only
improvement any ham can make is to always use copper ribbon in place of
round wires, to have lower inductance in that ground lead.
Usually, a feedline should not be a quarter wave odd multiple in length
at any band you use. Use of a balanced antenna tuner with open wire
feeders is best, but you can use a high quality line choke or 1:1 balun
in many cases, and 4:1 in other cases. Sometimes, you have to try it
out to find the best balun set up.
-Stuart Rohre
K5KVH
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