[TowerTalk] Tower planning

[K7LXC@aol.com]

In a message dated 05/29/2000 7:42:49 PM Pacific Daylight Time, 
jmarkum@n-link.com writes:

>     I will have a lot of questions in the future, but I would like to start
>  off with a few basic ones here.  I have been a ham for 20 years, but have
>  never erected a tower of my own.  I have been involved as a part of the
>  ground crew since age 11, so  I do have basic knowledge of the process.  I
>  would appreciate any assistance or guidance along the way.

     Well, you came to the right place. TowerTalk is a great place to ask 
questions. You can sort out the answers and see which ones are credible and 
which ones aren't.
>  
>  I live in a residential area, so I know that I will have to research zoning
>  ordinances, etc.  on towers.  I also live in relatively close proximity to
>  an airport, so that's another concern.

      How close? I think the ratio is 100:1 (I'm going by memory here). So if 
you want to go up 90 feet, you need to be 9000 feet from the airport.

     BTW, Bell County is a 70 MPH windspeed zone - the lowest rating they 
give - so no big deal wind-wise. (Windspeeds for all 3076 US counties are 
under Tech Notes at http://www.championradio.com.) You need to plan the whole 
installation with this in mind. 

>  I will be using Rohn 25g.  I can go up as high as my living
>  conditions/ordinances/airport will allow(I have 130 feet).  I am planning 
on
>  putting up a Force 12 C4S or C4SXL(any comments on these two antennas will
>  be helpful), a set of stack-11 Cushcraft 2 meter beams, a Cushcraft 2/440
>  vertical on top, and possibly a set of 440 beams similar to the stack-11's.

    Do you have a Rohn catalog? If not, you need one for planning and 
installation. 90' of 25G is rated at 15.3 sq.ft. @ 70 MPH so you need to 
observe this spec as well. 

     Are you going to get a building permit? A BIG question. 

     There is no appreciable difference in performance between the 2 Force 12 
antennas except on 40M where it's 2L vs. 1L with the 2L the obvious winner. 

>  I will probably use a Yaesu G-1000SDX rotator.  Will the tower/rotator
>  handle this type of wind load?  

     Sure. 

> I probably won't be able to go any higher
>  than about 50 feet (plus the mast if lucky), and am planning on using 2 
sets
>  of guys.  I had dreams of adding a moderate size 6-meter beam later, but I
>  don't want to put too much on one tower/rotor.
>  
>  Also, the guys are going to be a bit tricky to place, as I have a small 
back
>  yard, and the poles need to be back there.  Are 4 poles/sets of guys
>  necessary, or will 3 do?  I will definitely have more questions about the
>  guys later, such as what type, if torque arms are necessary, etc., but this
>  is more than enough for one day.  I know that I'm showing ignorance here,
>  but I would rather do it now in the planning stage than later after it's 
up!
>  I have really enjoyed the expertise on this reflector, and appreciate all 
of
>  the advice given.  Thanks in advance for the help.
>  
       Where do you get 4 poles/sets of guys? With the exception of the now 
out-of-production tiltover, ALL guyed Rohn (and other) towers use 3 sets of 
guys at 120 degree separation. Again, get the Rohn catalog (available from 
http://www.championradio.com). Are you proposing using elevated guy posts? In 
that case, you need to use 6-8" I-beam (eye-beam) but that's more of an 
engineering question. 

Cheers & GL,    Steve    K7LXC
Champion Radio Products

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