[TowerTalk] New Tower .. How?

[K7LXC@aol.com]

In a message dated 11/29/00 9:51:40 AM Pacific Standard Time, 
zs6arf@telkomsa.net writes:

> New tower consists of two triangular sections of 6 meters each (+/-64.5
>  feet),  (galvanized pipe) to give 12 meters (+/- 129 feet)
>  Have a commercially designed cage as well as the two hinged T-sections for
>  the tower to be connected to the base.
>  I gather it can be freestanding as no connections for guides. Intend 
putting
>  YAESU 1000DX rotator with 6 element Log Periodic (ATN)
>  
>  PLEASE give me guidance on:
>  
>  1)    The concrete base (what is the correct mixture and method of pouring,
>  will one square meter do (+/- 11 square feet)

    I didn't understand the size of your tower. Is this a commercial tower? 
If so, ask the manufacturer. If it's homebrew and you don't have access to an 
engineer, you can make some educated inferences from the Rohn catalog. Find 
an equivalent Rohn tower and  put in the appropriate base for your soil 
conditions and windspeed zone and you'll be pretty close. You could even 
over-engineer them too. 

    The Rohn catalogs are available at http://www.championradio.com.

>  2)    Best method to ground tower
    
    Run copper wire (#2 size or thereabouts) from each leg to at least two 
ground rods spaced by their length. You also need to ground your cables. 
Check the TowerTalk archives on www.contesting.com for more info. 

    I also have a reprint of the Polyphaser article about grounding for hams.

>  3)    The tower legs fits into the three pegs of the bottom T-section and
>  then gets bolted.  Will that be adequate.

    Is this the factory method? Can you post a picture of it on the internet 
somewhere? I don't understand what you're describing. 

>  4)    If the two 6 meter sections is connected on the ground and then to 
the
>  T-section, what is the best way to lift it up.  (i.e  block and tackle)

    Sure, block and tackle is okay. You can use a cable puller/comealong too.

>  5)    What is the minimum angle and height up the tower to use a block and
>  tackle.

    I'd attach the line about 2/3 of the way up the tower. It's helpful to 
have the block and tackle anchored as high as possible.

>  5)    When lifting the completed tower, at some point it will take strain 
on
>  the connecting part of the two 6 meter sections.

    See above.

>         These will also just be bolted. Should I take pre-cautionary action
>  here or should the legs be able to take the strain.

    What kind of precautionary action? Give it a try and if it starts to bind 
or something is really straining, stop and try something else. The legs will 
be able to take LOTS of stress so that's not the failure point. You're 
correct that there is a lot of stress when you're trying to tilt-up a tower. 
It's not a very tall tower so you should be able to do it.

    How about talking to Chris, ZS6EZ? He's built a bigger-than-normal 
station in your area and he's familiar with these questions.

Cheers & GL,     Steve      K7LXC
Tower Tech
Champion Radio Products

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