[TowerTalk] Prop Pitch Motor Rain Protection, Selsyn and Mast No Balls Bearing

[K7GCO@aol.com]

Who was it that wanted a picture of how I protect my Prop Pitch motor from 
rain?  I got a few reprints.  My system is simple with about a 6" can that 
fits into the ridge in the top of the PP and connected to the mast with a 
plastic spacer from the plumbing people. Any water that gets by the lip has 
drain holes.  I do strongly recommend another panel around it to take the 
direct wind blasts of rain, dust and snow as this really takes another level 
of protection.  Back in SD 3 years ago I saw where snow got into past doors 
and windows after a 24 hr 60 MPH blizzard and rain will do the same.  That 
way you only have to check it every 50 years or so or if it stops working for 
some reason.  The pictures shows my simple thrust bearing using the bottom of 
a 20' mast of 2 5/8" aluminum tubing with 1/4"wall riding on a 1/2" aluminum 
base plate about 5" wide. One of my towers has been on the house or aside it 
and the PP motor was at roof level for easy access if ever needed.  Long 
masts solve a lot of problems.  A smaller pipe telescoping inside the mast 
goes through the aluminum base plate prevents sidewards motion and connects 
to the PP motor.  No ball bearings to grease or rust and another advantage of 
the extra power of the PP motor even if speeded up.  The bottom of the mast 
rubbing on the base plate wears a slight groove perhaps .1" deep after about 
50 years of extensive use.  However it won't affect the angle of radiation.  
I paid $1/lb for the aluminum plate from Boeing Surplus and you can get 
someone to bore the hole in the plate for the PP pipe with a lathe or mill 
which I have.  

I can remove my PP motor easily as the cross braces are bolted to the tower.  
My 1/2" cog belt drive can be seen coming off the mast 5" cog belt plastic 
gear going to the 5" cog belt plastic gear on the selsyn.  It's upside down 
covered with a plastic pail.  I made aluminum slightly beveled side plates on 
the plastic 5" cog gear to keep the cog belt from slipping off.  This only 
took a few hours to make and has lasted over 50 years.  I got a bunch of the 
cog belt gears from Boeing Surplus but they are available commercially under 
"Belts and/or Gears" in the Yellow pages where I got the belts I needed.  I 
once used bike chains and sprockets but I had to keep lubricating the chain.  
The Lube would last longer on the chain if covered.  

If I ever get this Scanner working I could e-mail this and other pictures of 
my set up that has passed the "Mechanical Test of Time."  I've had virtually 
"No Maintenance" to a couple PP motors, selsyns, my tower set ups and 
antennas.  The biggest aid and a necessity is the big wooden tapered platform 
3' below the top of the tower.  It sticks out about 4'.  A lot of tower and 
beam problems get dalyed until the Spring if not done right.  Various 
conveniences of access and ease of working on the tower and beams greatly 
accellerates any maintenance of or antenna changes regardless of the weather. 
 I have flood lights for the area under the tower and varoius Miner's Lights 
for working on the tower or making adjustments at night.    k7gco  

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