Howdy gang,
The Question is: Can I use Ferrite to isolate a feed point on a tower?
I have a 133 ft tower that is insulated 10 ft above ground. I built a
collar out of 3/4 inch copper pipe that is insulated from the tower and
direct ground. I have about 34 quarter wave radials attached to this
collar. The tower sports a Cushcraft log periodic at 135 ft, and a
Cushcraft 40mtr dipole at 80ft. Both feed lines cross the insulated section.
I loaded the tower, feeding it at the insulated section, and got it "to
work." I checked my feed lines with a probe and they were hotter than a
heifer with out a brand. My signal reports were suspicious also, when I
compared them to what I was handing out to stations with dipoles at 20 ft.
I suspected the feedlines were coupling and shorting out the insulating
section at RF.
Prior to the 160mtr contest this past weekend, I unhooked the feed lines
that crossed the insulator and tied them up onto the tower. The tuning of
course had to be drastically changed. The feed lines were not near as hot.
The tower obviously improved and made a good showing in the contest.
My question is, can I load my cables with ferrite and isolate them at the
insulated feed point? Or will I have to keep disconnecting everything to
run it on 160mtrs. I could machine a switch that remotely diconnects
everything completely, but would the ferrite work?
I have provisions to shunt feed the tower, but I don't want to do that.
(long story)
73
Jay WC7M in Gillette, Wyoming
On the 1AB Ranch in Campbell County
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