In a message dated 4/27/05 10:11:06 PM Greenwich Standard Time,
n5pht@yahoo.com writes:
1- Antenna height. My plan is to put up an Optibeam
OB17-4 at about 82 feet (77' tower plus a few feet of
the mast and the OB17-4 would sit right above the
tower - so a height of 82 feet).
QUESTION: How would the performance differ if I
dropped one section of tower? That would leave 67
feet of tower and the antenna would therefore be at
about 72 feet? This antenna has 3 elements on 40
meters and that would be my most concern on the 10
foot drop? I don't think 10,15 or 20 would suffer too
much from 82 to 72 feet but I am not sure about 40
meters?
........no big deal.
2- Strength. The 45G will be guyed in two places.
What would be the suggested guying placements for the
77 foot and for the 67 foot? I would think for the 77
foot the first guy would be at 35 feet and the next
(and last) at about 65 or 70 feet? But would the 67
feet still be guyed about the same: 35 feet and maybe
then again at 63 feet or so. IF I go with this 10
foot less what would be the strength gain since I will
still be using 2 sets of guys.
Yup....35 and 70 will work fine........Use 1/4 inch EHS.
Bear in mind it is not necessary to have a crane 87 feet tall to put up an 87
foot tower. The entire tower can be lifted in one piece by picking it around
50 ft and then just lifting it.
Good luck.
Bill K4XS
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