[TowerTalk] Tower Installation Questions

[Jim Thomson]

Date: Fri, 24 Jul 2015 20:04:47 +0000
From: Daniel Hileman <n9wx at hotmail.com>
To: TOWER TALK <towertalk at contesting.com>
Subject: [TowerTalk] Tower Installation Questions

Hi All,

I am thinking of going with an AN Wireless HD70 or 80...probably with a TH-11 Hy-gain at around 70' and a 3 element 40M Yagi @ 85'. This is all new to me, and I am going to bring in people of experience (probably a crane to raise tower and yagis), however, I do have a question about mast raising. How do you winch or raise a mast from the top of the tower...say you install a yagi, then want to hoist the mast up with the upper yagi? How is this done from the top of the tower? 


Thanks and 73,
Dan N9WX


##  Do yourself a favour and use a 3 inch OD x .25 inch wall thickness,  4130 chromolly mast.
Typ they are 104-120 ksi yield strength. 
Don’t even think about messing about with a 2 inch OD mast..even if its  .375 inch wall thickness. 
A  3 inch x .25 wall will weigh the same as a 2 in od x .375 wall, yet the 3 inch mast will be one helluva lot
stronger.  You can see that effect on the arrl mast spread sheet. 
The 3 inch od x .25 inch wall thickness mast, in heat treated 4130 CM is the strongest thing there is. 
the only mast stronger would be the same 3 inch od... but with a .375 inch wall.

##  Then install mast steps.   Then you can easily get to the top yagi.  A 3 el 40m yagi will have its  DE +
balun right at the mast, or very close to it.   Then u don’t have to mess with removing the rotor, and dropping the
mast down several feet..just to get at the top yagi.   UST makes a mast raising fixture designed 
for their crank up towers,  to raise and lower a mast.... pita.   Even then, you have to still loosen the boom
to mast clamps on the lower yagi, so the mast will drop down. 

##  mast steps are readily available that will easily  do the job.   Mine are hb, and consist of 2 inch angle AL x.25 inch thick.
They are clamped to the mast with a single DX eng jumbo mast clamp, huge surface area clamp.  The top and sides of the angle
al are covered with that 2 inch wide x XXX long non skid stuff.    At the extreme ends, I use a single  .25 x 20 SS bolt + SS nylock
etc.   These small bolts protrude upwards....and used so you can feel them with your climbing boots...so you know where the
ends of the mast steps are. 

##  climbing a mast is not difficult at all, but you have to be careful, and proceed slowly, and use a pair of correct length lanyards.
Once at the top or whatever height up the mast  you want to be at, one of the lanyards is wrapped several times around the mast.
The 2 inch angle al is easy on the feet.   Install the heaviest duty, bomb proof balun etc, you can up there.  Done right, you should
not have to be going up there very often...if at all.

Jim  VE7RF