In a message dated 98-03-06 14:13:57 EST, wmal@taconic.net writes:
<< My
intentions are to place the T-8 a foot or two above the top of the tower
with nothing else above it. I think I'm in good shape so far....but what
abt the mast? What type of material and wall thickness. I've heard
suggestions from 1/2" walled aluminum (more expensive than tower!) to
radio shack masting (NOT). There seems to be a lot of ground between
those two ideas. I'm guessing there must be some rule of thumb to this. >>
Hi, Bill --
You are correct to consider the mast question. Many people use unsuitable
masts and suffer the consequences.
Your proposed installation though does not present any potential
problems. The problems arise when you start stacking multiple antennas on the
mast. For one antenna one foot above the top of the tower, you can get away
with just about anything including 1.5" (1.9 inch OD) water pipe or Schedule
40 pipe. Even aluminium 6061-T6 will work. The bending moment on the mast is
minimal with just one foot of mast between the thrust bearing and the antenna.
OTOH, all bets are off if you have more exposed mast or start installing
more antennas on it. At that point you need to do more homework.
73, Steve K7LXC
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