Hi all,
I wanted to bring you up to date on my 160m antenna situation.
I wanted at first to put up a T top Marconi, and I did, but then we all
decided it needed to be longer along the top wire. I took it down and
figured I had to add 85 feet total. While I was at it, I measured the
vertical wire and it turned out to be only 44 feet long. I decided the
tree was too low and abandoned the Marconi idea. I had already laid down
32 100-ft. radials under the center point...
So I went back to the Inverted-L idea. I ran a #12 stranded wire up the
side of the tower, stand-offs were about 4' out. So that's about 68'
vertical and then 135-68=67' horizontal, the total length is 135'. I
wanted it to be resonant at 1.800-1.850, hopefully. Then I had to move
all the #@$%^ radials over to underneath the tower. I added an RFC and
two spark-gap modules from the vertical wire to ground. The radial plate
is NOT grounded to earth. I hooked up a short length of LMR-400 from the
antenna to the antenna switch; total coax length out to the antenna is
about 265 feet.
Came inside the shack checked the SWR curve....it's very nice, between
1.1:1 and 1.3:1 for the frequencies I mentioned. Seems to be pretty
broad, at least enough for any 160m CW.
I only have one question (other than 'how does it work on DX?' which
will be answered in the next few nights!) and that question is, do I
need a 1:1 unun to isolate the feedline from the antenna to possibly
prevent TVI/RFI or other overloads? The 900' beverage takes off about
25' from the base of the tower. I think a couple of the radials wound up
going under the beverage, which is up at 7' off the ground. I plan to
hook up an ICE RF-limiter before going QRO with this system.
Appreciate all your help and thoughts!
Regards,
Paul
WY7I
Chromo, CO
DM67PD
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