[TowerTalk] Rohn FK 25 & KT34XA

[K7LXC@aol.com]

In a message dated 06/05/2000 3:46:34 PM Pacific Daylight Time, 
jskatz@sk.sympatico.ca writes:

> First let me thank all of you who responded to my question about the
>  KT34XA. I think I have been suitably forewarned about the need to
>  inspect and service this antenna on a regular basis.

     While ALL tower and antenna systems should have an annual inspection, 
I'm not sure what sort of service you would perform on a regular basis. The 
trick is to do it right the first time.
>  
>  I have a change to purchase a discontinued Rohn FK 25 (58' fold over
>  tower).  I understand the 25G accessories fit  the FK 25.. The
>  recommended guying radius is 18' but for a variety of reasons I think I
>  will guy it at 32'.
>  
      Uh...maybe not. The LXC Prime Directive says to "DO what the 
manufacturer says". That being the case, guy it where they say. While their 
drawings for other tower heights and windspeeds are just ONE guying scenario, 
the foldovers are much more critical in their installation and use. 

>  Questions:
>  
>  Do you think this tower can handle a KT34XA and a T2X?

    Maybe. What sort of building department windspeeds do you have? What kind 
of ice conditions? I sort of visualize VE5 as white in the winter. If so, you 
may need to allow for some radial ice - 1/4" to 1/2 " being typical. If 
that's the case, then you'll need to downrate the tower capacity 
significantly. 

     You may want to get an engineer to run some calcs for you based on the 
ice and windspeed data to insure that, yes - the tower can handle it. 

>  If yes, what precautions should I take to ensure that I do not have to
>  service it in the middle of winter.

     DO what the manufacturer says and DON'T make any of the Ten Most Common 
Tower Building Mistakes (which is found under Tech Notes at 
http://www.championradio.com). Make good electrical and mechanical decisions 
and you shouldn't have any problems. 
>  
>  Also I have been advised to use the K factor instead of the antenna
>  surface area to determine if the FK 25 can handle a KT34XA. What is the
>  K factor and how does on calculate it?
>  
     K Factor (also known as Effective Moment by Hy-Gain) is turning radius 
times weight. The K Factor (EM) for the XA is 1462 ft-lbs. You need a Ham IV 
or G-1000 for this big antenna. 

Cheers & GL,    Steve   K7LXC
Champion Radio Products
Tower Tech 

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