W3LPL is the master of this stuff. Frank has a lot of the stuff in the
air. Best to get him on the phone.
What I recall of my converstation with him, is that it comes shipped
in large coils (8 feet in diameter?), that there was a minimum order
(don't remember what), and it was a bear to work with (it sproings).
The stuff has to be handled at all times with thick leather gloves. It
has a special termination similar to the quick-grips used on regular
steel guys, no substitutions allowed.
In your case I would go 100% philly (or fiberglass). The pattern
distortion even exists for the lowest set of guys. The free space
pattern of these antennas has very little reduction straight down. The
steel guys will definitely cobble the front-to-side.
With regard to the fixed mounting, would one of your tower faces
happily be edge on to 45 degrees? I'm putting up my Trylon that way by
design, just to take a lower C31 fixed on EU. You can drill a couple
of plates to fit the boom and the legs. (In the case of my Trylon, I
will use extended bolts, and holes in the plate which match the tower
bolt holes, and put them in as the tower is built. This works for me
because I have zero hope of rotating that beam because it's below the
tree line. NE is the most consistently useful direction for 60-65')
Otherwise, you might want to use a swinging gate mount without the
rotator. I'll bet that you end up wanting to rotate it, or at least
wanting to have it different directions for different contests.
On Tue, 16 Mar 1999 13:01:28 +0000, you wrote:
>I'm planning to add a second C-3, fixed on Europe, 28 feet below my top
>antenna, to my 100 ft Rohn 25 tower this summer.
>My top set of guys have 21-foot fibreglas insulators at the top end, but
>are unbroken from there on down. Modeling suggests that they will really
>mess up the pattern of the stack, not to mention when using the lower
>I plan to go over to totally non-conductive guys for the top set, and move
>my insulators down to the middle set. Question is, is Phillystran the only
>practical option? A few years ago, some guys in PVRC bought a large
>quantity of Polygon(?) fibreglass guy rod, which I understand is only about
>1/3 of the cost of Philly, but as I recall there were minimum quantity and
>handling issues. Can anyone enlighten me on this option?
>Second, since I plan, initially at least, to fix the lower antenna on
>Europe, it seems as if just about any 2" steel tubing will do for a mount,
>simply rotating the boom-to-mast clamp on the C-3 to attach to a horizontal
>tube. If this is how it's often done, the question is how best to attach
>the tube to the tower. Would it work to U-bolt it to one leg and one
>horizontal tower rung, or should I plan on something like an accessory
>shelf, u-bolted to all three legs, with the tube in turn u-bolted to the
>73, Pete Smith N4ZR
Crushing will be.
Guy Olinger, K2AV
Apex, NC, USA
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