This load equals 39 sqft projected area including exposed mast. About
75% of the tower rating at 100 mph. I live in an 80mph zone.
Have the load checked by a professional engineer. Most towers are
specified for load at the tower top (or within 1 - 2 feet). Spreading
the load up the mast can greatly increase the effective load on the
tower.
73,
... Joe, W4TV
On 2018-04-24 7:19 PM, kstover@ac0h.net wrote:
OK Tower Talkers. I need wisdom and guidance.
I am finally in a position to start building my retirement station meaning a
BIG upgrade in the tower and antenna department.
Here is my plan.
70’ AN Wireless HD tower
25’ 3”x3/8 wall 4130 Chromoly mast, 20 foot out the top.
½” hard line from the man cave to the tower. I haven’t decided where to put
the coax switch yet, top or bottom.
Rotator, either a K7NV prop pitch or an Alpha Spid BIG RAK Anything with PST
in the name need not apply.
Antennas. I have to do all this on one tower.
Right now I’m leaning toward a JK Mid-Tri (20-10), a JK 1712 Jr for WARC .
and a 402T for 40m, in that order up the mast separated by 10ft.
16 sqft for the Mid-Tri, 9 sqft for the for the 17/12 Jr. 9sqft for the 402T
and 5 sqft for the mast.
Another possibility is an Optibeam 11-5 for 20-10 WARC inclusive, the 402T
at the top then a six or seven element 6m beam in the middle
This load equals 39 sqft projected area including exposed mast. About 75% of
the tower rating at 100 mph. I live in an 80mph zone.
The mast will take the load all the way up to 125-130 mph depending on
antenna scenarios.
For the low bands I’m going to shunt feed the tower
SteppIR is not an option. They break too much. Save the anecdotes.
Same thing for PST whatever. They break too much. Save the anecdotes.
Since my disability my climbing days are pretty much over. I need to pick
products that are built hell bent for stout.
Nobody makes a crankup tower that will take that load. I could downsize the
antennas and go with a xr5-jk but it’s two elements per band on five bands,
I still haven’t figured out how the Navassa 5-jk works. 5 bands on a twelve
foot boom. Must be some “Weird Science” (Quantum Mechanics) going on.
Thanks for the input.
R. Kevin Stover AC0H
ARRL, FISTS, SKCC, NAQCC and a bunch of other acronyms.
One of the guys that made sneakernet irrelevant, in my little corner of the
world.
“If it doesn’t work the first time you push the button it won’t work the
20th…Just stop.”
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