Hi
I've been reading the ON4UN book and antenna articles online on and off for a
couple of years now but I thought I'd share my situation with some more
experienced Guys on here to see if I can perhaps find some new information and
ideas.
I have a modest HF/6 station that covers 40-6. I have a painted 3 section 60ft
Versatower (suspect v. poor electrical connection between sections) with an
Optibeam OB1-4030, Optibeam OB9-5 and 5L 6M Yagi all mounted on a 15ft stub
mast and fed into an Array Solutions Ratpak. (Antenna pic on QRZ) The 6M Yagi
has grounded elements but the Optibeam elements are insulated from the boom and
tower. The station is working nicely now so I feel it's time to add an 80M DX
TX antenna. I am interested in 3.5MHz CW only, so bandwidth/phone etc not an
issue.
In the past I've tried an 80M coax fed inverted vee with the apex at 60ft - as
expected dynamite out to a couple of thousand miles but no good for DX. I've
ruled out the possibility of shunt feeding the tower because of the Optibeams
and the poor connection between sections. So currently I'm left with two ideas:
MFJ-1792 or Butternut HF2V mounted 50ft from the tower (landscaped gardens
prevent mounting anywhere else)
Inverted L hanging off the tower with approx 60ft vertical section.
What I guess really matters is the tower's resonant frequency, looking at the
details above, would anybody like to guess? Because the Optibeams are insulated
from the tower do they still effect the tower's resonant frequency? If it is
resonant close to 80M I guess the RF fed into a vert 50ft away would see it as
a parasitic element?
In the worst case scenario, if the tower messed with a vertical I could always
lower it before operating on 80M but it's not ideal.
Apologies for any stupid questions and Merry Christmas to you all!
Jack G8DX
Sent from my iPhone
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