[K4RY] No Meeting Tonight + Tower Update

[Kris Kirby]

On Thu, 28 Sep 2017, John Klingelhoeffer wrote:
> I'm not sure what advantage going to 40 feet would make (other than 
> taking more lightning strikes!), but have you considered using Rohn 
> 45G tower rather than the 25G that is currently on the roof?  
> 
> Using the 45G gives significantly larger cross section to the tower.  
> It may be with this larger cross-section tower, the same anchor points 
> can be used as before to stiffen it even more.  

45 is also much easier to climb. UABARC had 50 feet of Rohn 45 from the 
1980s to 2010, likewise with a Moseley TA-33 and a Ringo Ranger. You may 
consider multiple non-penetrating roof mounts for anchor points. If the 
roof support structure is strong enough, there are non-penetrating roof 
mounts that can support six foot C-band dishes (TVRO from the 1980s). A 
practical exercise in statics and dynamics.

3/8" 17-strand stainless steel "aircraft cable" is fairly universal for 
fall protection systems, tying down aircraft, and guying towers, if you 
can get it donated.

Do be aware of nearby high-voltage power wires. 8/12 kV is pretty common 
in the south. You don't want to find yourself with the antenna tip at 75 
feet from the base, with the base 75 feet from a 12 kV three-phase 
distribution line. Or a dipole where it could blow into the line if 
broken by a storm.

73,

--
Kris Kirby, KE4AHR
Disinformation Architect, Systems Mangler, & Network Mismanager