Topband: Marconi: out, Inverted L: up at WY7I

[WY7I]

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