I just installed a Force 12 EF-240S about 5 feet above a C-3 tribander, and
am seeing fairly severe interaction, evidenced by big changes in the C-3's
resonant frequency and SWR bandwidth on 15 and 10. The gain and pattern of
the C-3 seem OK, but my initial impression is that the '240S doesn't show
much F/B or front/side. I'm well aware that the spacing is tight by
comparison with that usually recommended for Cushcraft 40-to-tribander
spacing, but Tom at Force 12 says that he has seen this combination as
close as 4 feet without significant interaction, which is why I did it in
the first place.
I have about 18 more inches available on the mast, and will be moving the
EF-240S up that little bit more ASAP, as well as trying the 90-degree turn
option. But in the meantime, I wonder about the experience of others out
there, who have what they consider good-performing EF-240S installations.
What do you regard as typical F/B and F/S ratios?
73, Pete Smith N4ZR
n4zr@contesting.com
"That's WEST Virginia. Thanks and 73"
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