On 10/6/2010 8:34 AM, Jim Thomson wrote:
> How close can you get a 20m yagi, below a 2-el 80m yagi ?
> I have an option to use a F-12 Sigma 280-S shortened 80m yagi
> at the top of the mast, with the F-12 340N at the bottom of the mast.
> Spacing between the two of them would be 10.5' If possible, I
> would like to sandwich my F-12 520 [20m yagi] between the
> 80 and 40m yagi. Apparently, you can mount any other F-12 HF
> yagi within 36" of the 3-el 340N yagi.
An e-mail to Force 12 brought me an answer for my Force 12 antennas in
less than 24 hours.
This is not the 40 meter antenna, but the reply was prompt.
Between the C19 XR tribander and the "old" WARC-7 is recommended as 16'
with degraded performance (although not bad) using closer spacing. The
"new" WARC-7 can be within 3 or 4 feet of the C19 XR.
> If I put the 20m yagi
> 4' above the 40m yagi... that would leave 6.5' between the 20m yagi
> and the 80m yagi. Will this work ?? If it doesn't, one option is
> to remove the 20m yagi. Another option is to place the 80 and 40m
> yagi's at right angles to each other [ no 20m yagi at all] . I don't think
> is required, but would minimize the total wind load.
> Plan B would be to replace the 2-el 80m yagi with a
> 80m rotary dipole...with dipole inline with 20m/40m booms below it. IE:
> is then at right angles to both yagi's below it. Due to day time height
> the above options are strictly an after dark scenario. I don't have any
> software on hand
> to model any of the above.
> Thanks.... Jim VE7RF
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