Well, my tower crew has just been given the order to replace all steel guy
cabling on my 180' tower with non-metallic Phillystran. I decided to make
this one structural change in the hope that I will never have to worry about
the effect of guy cabling on the four 160-meter patterns.
I've spent the better part of the day zeroing in on what I want for the
upper bands. Whatever I end up with will be mounted on a 20' or 24' 4130
Chromoly mast at the top. I have narrowed the decision to the following
possibilities:
1) As indicated earlier this week, I was giving strong consideration to the
Force 12 C-4XL (40M-10M) on a 30' boom.
2) A Force 12 C3 together with a Force 12 EF-240X
3) A Force 12 C3 with a Cushcraft XM240
After reviewing the KA9FOX's archives, the potential interective effects of
choices 2 and 3, are leading me to believe the C-4XL is the most predictable
alternative. The 40-meter monoband performance of the other two is better
by approximately 1dB. What is a recommended stacking distance for options 2
and 3?
A few more questions:
Assuming options 2 or 3 at 180+ feet, is there much difference in
performance or interactivity if the tribander is placed on top or below the
40M antenna?
Cushcraft specs a F/B ratio of 20-25 dB on its XM240. For a two-element
Yagi, are they stretching the truth a bit? F/B on the C-4XL and EF-240X is
rated at 15 dB.
In reviewing the various rotator possibilities, I would like to "damn the
torpedoes" with a Yaesu G-2800SDX. Can I go wrong with this combination of
mast, antennas, and rotator?
-Paul, W9AC
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