[TowerTalk] guy posts math

[Jim Thomson]

Date: Sun, 19 Jul 2015 15:07:44 -0500
From: Lee George AK4QA <ak4qa at msn.com>
To: Kelly Taylor <ve4xt at mymts.net>, Bill Aycock
<baycock at mediacombb.net>
Cc: Tower Talk List <towertalk at contesting.com>
Subject: Re: [TowerTalk] guy posts math

Is amazing that you get anything  built.  so I transposed  A Ad hoc formula Email That I'm sending from my Telephone Yeah. Yes it should be one foot down for every three foot up For a wooden pole. Read my page And let's see if you can do what I've done With what I have.Thank you guys for nothing. One of these days I'm gonna learn That's These Newsgroups Are useless.

## I worked for the local telco for 34 years.  heres the formulae for wooden poles...used since day 1..and used across  canada and the usa..and still used today. .     Depth into ground =   10% of the height above ground..PLUS 2 feet ! 
IE:  for a 40 ft pole above ground, depth into ground  = 4 + 2 = 6 ft.    For a 30 ft pole its 3+2 = 5 ft.    For a 100 ft pole its 10+2  = 12 ft.   For a 20 ft pole its  2+2 = 4 ft. 

##  For elevated guy anchors radio towers  whole different ball game, since the  steel tubes are into concrete.    wooden poles are NOT into concrete.    1st, u didn’t tell us what kind of 100 ft tower your buddy has.  next we have no clue of the total windload
on the tower. 

##  A friend in wash state has a  100 ft of rohn 45... with several yagis on the top and on the sides.   He used 6 inch OD tubing, sched 80,  implanted 6 feet into the concrete..and 6 ft above the ground.   Hole in grnd is  3 ft square and 6 ft deep.  Just over 2 yards of concrete used.     Steel plate, aprx  2 ft square is welded to the bottom of the 6 inch tube.    Then 4 x rocket fins welded between  lower portion of steel tube and the base plate.    Entire mess was hot dipped galvanized.  4 inch wide x 12 inch tall  x 1/2 inch thick steel plate is  welded  to side of steel top..at the top.   Holes punched into the 4 x 12 plate..... b4 welding.    holes used for  guy anchor terminations.    Concrete dumped into hole.   Vibrator used  on the concrete.    NO back guy required.  The tube is shimmed slightly such that its JUST 1/4 inch back from dead plumb.     Ok, once concrete dried.....the inside of the steel tube is  filled with concrete.   u do a bit at a time..and its tamped down. 

##  he had the above config designed by a professional engineer.   Been up for years, doesn’t budge.   held everything from  stacked optibeams to monster steppir   to m2  4 –el 40m yagis.   snow loads, ice loads..and high winds.  zero problems.  

##  other friend has 190 ft of rohn 55 up.  14 yagis on the rotating tower..including 80m yagi on top. .  3 x elevated guy anchors used.    But these are 10 inch diam,  sched 80.   Same deal with base plate and rocket fins.  5 ft square x  6.5 ft deep  concrete base.   tube is 7 ft above grnd.
inside of tube filled with concrete.  Tube is slightly  out of plumb by 3/8 inch.    no back guy used.   Welder stuff some steel plate inside the top of the tube and welded that in.... to beef it up a bit more.   4 x sets of guy wires.  Guy anchors in that case are  175 ft out from the base of the tower.   been up for several years now.   Doesn’t budge.    The base of the concrete hole can be flared a bit..and ditto with the rebar.    That increases the  strength by a bunch.   typ base flare is  an extra 1 ft on all 4 x sides.... and starts  18 inchs up  from the bottom.  

later............ Jim   VE7RF