Jim,
I finally had a few minutes to go back and measure the antennas at the feed
point. I found 1 antenna slightly off so I adjusted it so both are now
relatively close. Antenna A was R=32 X=9 and Antenna B was R=38 X=7 centered
at 7.100. I had several people recommend adding a choke at the feed point on
each antenna. I may have to add some beads. Thoughts? I also like the idea of
implementing a simple LC network something like Gary NA6O suggested. Now, I am
second guessing myself and maybe should have gone a different route.
DaveKB8NNU
On Sat, Sep 6, 2025 at 5:52 PM, R. David Eagle via
TowerTalk<towertalk@contesting.com> wrote: Hi Jim,
I am going to remeasure the antennas tomorrow if the weather improves around
here. I somehow misplaced the numbers. But anyways....The 2 quarterwave
vertical sections I built out of 14G THHN held up by two HD spiderbeam poles
mounted on 4x4's. The antennas are spaced 1/4 wave aprat. The feedpoint is
about 6ft off the ground so I could run 2 quarter wave elevated radials off
each. Currently, the radials are running parallel between the 2 antennas. The
antennas are mounted NE - SW along the edge of hardwood forest with no other
metal near the antennas. I wound a small impedance transformer this spring to
hopefully take me from mid 30's to something closer to 50 but that didn't help
much either. I was considering going the route of putting together a small LC
network....but then I would have to have a means of switching that as well from
when I go Broadside to endfire......or maybe not.
DaveKB8NNU
On Saturday, September 6, 2025 at 11:05:02 AM EDT, Jim Lux
<jim@luxfamily.com> wrote:
what did you expect to see?
What are the impedances you see at the two verticals,without the coax, and with
the other antenna "open"
On Fri, 5 Sep 2025 23:55:52 +0000 (UTC), "R. David Eagle via TowerTalk"
<towertalk@contesting.com> wrote:
Hello all,
Let me preface this by saying this - I am NOT a phasing expert by any means so
I thought I would tackle a new antenna project this summer and maybe learn
something....or lose more hair! So any ways...I decided to put up a pair of
phased 1/4 wave verticals and phase them via the Christman method. Each
antenna has 2 raised radials. I ran across an article by W4NFR where he did
exactly what I am attempting, BUT I am getting different results....naturally.
I tuned each vertical to 7.100 exactly trying to get the lowest possible
reactance on each. I checked and double check the RG-213 71 degree delay line
and the 84 degree feeds to the verticals. Now, here is the puzzling part -
when I put everything together in my homebrew directional switch box, my
resonant frequencies are considerably higher when I switch between Northeast,
Broadside, and Southwest. The resonant frequencies are near 7.450-7.500 where
R=39 with X=6.
So I must be missing something here.....Anyone else had success with this?
Any help would greatly be appreciated!
DaveKB8NNU
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|