If you have not done so, this project would be worth spending a little time
modeling to see what the expected results should be. Are you seeing a
directional change and the frequency shift is your only concern? I read the
W4NFR article
https://www.moneysmith.com/W4NFR/40%20Meter%20Phased%20Verticals/40mpv.html
and he noted an SWR increase using Christman Phasing so he used a tuner with
his array. W4NFR stated that his individual verticals had a 1:1 SWR, they
appear to be just directly fed in the photo.
GL with this!
John KK9A
David kb8nnu 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
|