Terry,
You can use a pully system to get more travel out of the 4 foot "throw" of
the actuator. Secure one end of a cable on the pipe, put a pulley on the
actuator, run the cable over the pulley, and secure the other end to the
tower. Now, 4 feet of actuator movement will yield 8 feet of pipe travel.
-Rex-
K1HI
Rex Lint
Merrimack, NH
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Terry Price
Sent: Tuesday, March 17, 2009 6:58 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Bandwidth of a 1/4wl 80m vertical
Thanks to all that responded. I've decided to use an old Rohn 25 base that
already has 60 radials down as an experiment. I'm going to erect an
insulated 45 foot #25 tower with a standard top that accepts a 2" mast.
There is a place close to me that sells irrigation tubing in 2" X 30 foot
lengths. I am going to attempt to use a standard actuator off an old TVRO
dish to raise and lower the 2" pipe in and out of the top of the tower by 4
feet, the limit of the actuator, to change the match between the low end and
3800 which is about as high as I ever go, if I get more that's fine.
Decoupling of the motor control leads and insuring the tubing will move up
and down through the tower without binding will be the two biggest
challenges. If it works, one leg of the 4 square will be done!
Terry
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