Here's an intriguing idea. It's for 160, but there's a section on getting it on
80.
http://www.w0uce.net/K2AVantennas.html
73, Mike NF4L
On Dec 27, 2012, at 10:50 AM, Jack White <m5pro@hotmail.com> wrote:
> 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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