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[TowerTalk] Force 12 advice please

To: <>
Subject: [TowerTalk] Force 12 advice please
From: (
Date: Wed, 9 Apr 1997 10:37:50 -0400 (EDT)
In a message dated 97-04-08 21:37:35 EDT, you write:

> Ok fellow hams, I have seen several things about force 12
>  and now have their catalog in hand.  It looks to me that
>  this is a compromise antenna seeing that there doesn't look
>  to be enough elements per band, if you follow what I mean.

     Generally it's boom length, not number of elements, that has the biggest
affect on performance.  Whole books are written on this topic, I suggest you
get one.

>  Maybe I am wrong but I am wanting to erect this 100 ft 
>  tower that is laying out in my back yard.  I have a 4 
>  element, 20 year old Swan tribander on a 24 ft boom. And I 
>  had planned on putting a 2 element 40 meter cushcraft yagi
>  above it at 110 ft.  

      20 years is admirable service from an amateur HF antenna.  Will it make
it through the next sunspot cycle?  Maybe.
>       My question, is it worth the $900 to invest in 
>  this force 12 that has "all bands"  like the c4xl model?
>  Boy, I would hate to see this thing wiped out by lightning,
>  wind, ice or whatever at this altitude not to mention the
>  loss of dollars, time, and effort involved in replacing it.
>       I am not saying that the Swan would not do the same
>  thing but it was basically free of charge to me.  

     Why would the Swan be impervious to the wind, ice or whatever that you
mentioned?  Put up the Swan if you trust it and replace it with the C-4XL
when it dies.

>       Next question for you that have experience in rotors,  what is a good
>   I am currently looking at 
>  the yeasu g-1000sdx.  It claims to rated at 23.5 sq. ft.
>  Is that realistic?  I have heard of a few of my friends
>  complain cause they had to repair or replace a tailtwister.

     You need to consider the K-Factor of the load on the rotator which is
the weight of the antenna times the turning radius added together as opposed
to just square footage.  If you want to do your homework, an SASE will get
you a free copy of my 3-part series on rotators that appeared in my Up The
Tower column in CQ Contest magazine.  Send to TOWER TECH, Box 572,
Woodinville, WA, 98072.

     You'll have to repair or replace ANY rotator at some point. 

      BTW, the new MARC program calculates the K-Factor/Effective Moment of
antenna loads and recommends rotators for you.  MARC also calculates the
bending moment on the mast of any antenna system, something else you need to
take into consideration.

>       So that I only put up one tower, one antenna 
>  system, and one rotor for many years to come without 
>  spending $5000, is there an answere for me?

     In 25 words or less?  I have a reprint of a talk that I have given (just
last weekend at Fresno for example) called "Building A One Tower Station"
that you may want to read.

     You didn't mention what county you're in for wind speed and planning
purposes.  Let me know and I'll look it up for you.  Are you going to get a
building permit?  What kind of tower are you putting up?  Building a tower
and antenna system is an exciting project but there are many ways you can get
yourself in trouble.  Keep asking questions on TowerTalk and you'll mostly
stay out of trouble.

73 and GL,  Steve  K7LXC

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