If the feed is balanced, thus the currents in each side of the line are
equal and are 180 degrees phase difference, thus being current fed, there
won't be any RF in the shack. Any unbalance in currents or phase will
require the ground system to carry the difference in power.
In practice it is easy to achieve a balance of 5% or better with reasonable
installation means. With a 5% difference the amount of RF in the shack is
nil even at legal limit power.
I run a balanced antenna system at legal limit with no ground on the
station. Oh yes, the 3rd pin safety ground is in place. The #10 dedicated
4 wire AC power feed {neutral, ground, L1 & L2} from the breaker panel to
the operating position is some 75 ft. The station is on the 2nd floor and
in the mid part of a wood frame structure. No RF in the shack, no TVI or
BCI or telephone problems. Balance is the key to success. How long is the
feed line? Long enough to connect from the center of the antenna at the top
of the tower to the operating position, thus about 75 ft or so. Purchased
100 ft and put it in place and cut off the excess.
73
Bob, K4TAX
----- Original Message -----
From: "Scott Harwood" <scotth@hsc.edu>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, January 31, 2006 5:34 PM
Subject: Re: [TenTec] openwire feed OT
> Thanks for the trip down memory lane, Chas. I had such a tuner and it
> worked great. The parts are still around.
> On a related subject, anyone have any thoughts on the ideal lenght of open
> wire line to feed a 80 - 10 meter loop to keep RF in the shack to a
> minimum?
> Scott K4VWK
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