Greetings fellow TTers,
Last summer (when I still hoped I could get my tower permitted and erected
before the rainy season) a couple of you responded to one of my questions by
suggesting I contact or check on some postings by Bill Meeker. I can't find
Bill in the From column of my inbox so perhaps he is using his call sign,
which I don't know. Bill, are you out there? Anyone know what "name" Bill
posts under?
A much belated update of my project:
Instead of erecting a tower, I spent last summer and part of last fall: A)
getting permission for my tower from the local community development
department, and then B) satisfying the engineers at the building department
that my tower would be safe. Got the final approval on November 28th, which
in Northern California is much too late to start digging a foundation unless
you like tying rebar under water. The building dept gave me a plan check
extension until June of this year and I picked up the permit last week.
The AN HD-80 tower base is on the way and we start digging next week. I
will post a link to photos of the project as it progresses. Some of you may
recall my dilemma and questions from last summer. I can't get a crane in to
my location so I've ordered the tower unassembled (also saves big bucks on
the freight) and will put it together on site like a giant erector set. I
will build it around that "monster mast" as we discussed last summer. I'm
planning to use three plates: the top for the bearing, of course, and the
bottom for the M^2 OR-2800 rotor. The mid-plate will have a static mast
clamp on it. That's a device that looks a bit like a thrust bearing without
the bearing part. It has four large bolts, which serve as set screws to
hold the mast in place while the rotor is being installed/serviced. I'll
back it up with muffler clamps on the mast.
Dan, at ANW, suggested a 6' spacing between the rotor plate and the top
bearing, and a 3' spacing between them and the mid-plate. If any of you
have experience with this or a similar arrangement, I'd like your comments
on this spacing. The mast will be as long as I can get it (21' minimum to
as much as 24'). It will have 6.5 sq-ft (probably a F12 EF-230/240) at the
top of the mast and 10 sq-ft. (StepIR 4L) as far below that as the mast
length will allow, obviously to minimize the interaction between the
antennas. I may stick a small (< 2sq-ft) VHF Yagi on a fiberglass mast
extension at the very top.
Bill, I understand you have analyzed and perhaps installed a similar stack.
I'd like to hear your findings. (Or anyone else.)
I'll have a link to photos soon and will inform the group of what I have
learned along the way.
73 - JC, k0hps@amsat.org
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