Good afternoon,
Just about done assembling a TH11DX and Discover 7-3. I am planning to install
them atop a UST HDX-589 tower, and have a few questions regarding the optimal
arrangement.
The TH11DX weighs approx. 88lbs, and the 7-3 weights approx. 98lbs. Wind load
is 12.5 sq.ft. for the TH11DX, and 9.0 sq.ft. for the 7-3. Should I stack
based on weight, or wind load? Anotherwords, should I place the 7-3 just above
the top of the tower (thrust bearing), and the TH11DX above it, or place the
TH11DX just above the thrust bearing, and then the 7-3 above it?
Also, how far should I separate the two? I seem to recall reading 10ft or so,
but I really don't want to have this heavy of an antenna (either one) 10ft up
the mast if I don't have to. The mast is the UST M20R reinforced mast, but I
believe the inner reinforcement only extends so far up the mast. Anyone know
how long the insert is? I'm guessing it is only a few feet above the thrust
bearing. Maybe later when I get home I'll slide a tape measure into the mast
and try to figure it out if no one already knows.
The TH11DX's boom support needs to be 2ft above the boom-mast bracket. The 7-3
needs 5ft for the support cables. I was thinking of placing the 7-3 just
above the thrust bearing, maybe a foot or so, then placing the TH11DX just
above the 7-3's boom support bracket, which would be approx. 5ft above the
7-3. Anyone have any opinion as to this arrangement?
While I am at it, I had two thoughts as to getting the antennas onto the mast.
The first is to raise the tower so that the mast is about 12-15ft above ground,
then split the booms at their splice points, install the middle 3rd portion of
the boom, then raise a few more feet, install top thirds of the TH11 and 7-3,
raise the tower verticle, then rotate the rotor 180 degrees, then lower the
tower again, and join the remaining 3rd of the antennas to the mounted booms.
The other option is to just install the boom-mast brackets on the mast, then
raise the tower. Then either rent one of those scissor-like platforms to raise
the antennas (and myself) up to the mast brackets. I also have a neighbor who
owns a bucket truck, and he has offered me the use of it. Anyone use a bucket
truck (like the CATV or Verizon van style) to raise a 100lb antenna and 200lb
man? Would you consider that a safe move, or a crazy idea?
Thanks
Eric
K2WD
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