[Towertalk] My New 40M Antenna
Jan Erik Holm
sm2ekm at telia.com
Fri Dec 19 16:04:34 EST 2003
Sorry but this is the hard way to do it. It is no
problem to tram antennas complete, tuned up ready
to go just bolt to tower. 3 el 40 on 12m boom is
not a very big antenna to handle either.
Years ago when I put up my first 40 Yagi me and
my wife tramed it up without a problem, that was
a 4 el full size on 18m (60 foot) boom and weight
was approx 300 pounds. Just tramed it in to place
and bolted it to tower and hooked up feedline and
then cq dx cq dx.
73 Jim SM2EKM
----------------------------------------------------
Juhan Põldvere wrote:
> Re http://www.qsl.net/nidxa/kb9cry/kb9cry_40meterAnt.htm :
>
> Lovely pictures Phil! Thank you.
>
>
>>Problem: How does one hoist up a large antenna without it getting it
>>caught in tower guy wires, especially those top most guys?
>>Answer: Helicopter (Expensive), Crane (No Access), Tram (Never tried it
>>but always a first time)
>
>
> There is a fourth way, which we used to put up a stack of full-size 3-ele 40m
> yagis (these things are heavy - 12m(40 foot) boom, 22m(~72 foot) reflector)
> at ES5TV's this spring:
> ( mast and tower pictures at http://www.lhv.ee/images/files/es5tv.htm )
>
> 0) Think it over **0)
>
> 1) Put a pulley to the top mast above the beam's attachment point, and
> another to the tower near ground level. Route a hoist rope (we used a cheap
> polypropylene less than 1/2") up along the tower, through the top pulley back
> down to a winch in safe distance from the tower **1).
>
> 2) Attach the reflector and director temporarily to the boom (don't use
> locking nuts!). Find the centre of gravity of this system and mark it on
> the boom. Unbutton the elements.
>
> 3) Hoist the boom up the tower vertically, secure (SECURE!) it to the
> tower so its upper end is above the upper guys. I prefer the director end up.
>
> 4) Raise the "upper" element (director) and attach it to the top of the
> boom. Well, if the boom's low end is above the second set of guys, start with
> the "lower" element (reflector).
>
> 5) Raise the "T" so the boom's tail is above the lower set of guys. Have
> the boom through rope loops so it can't go sideways. Secure the "T" to the
> tower.
>
> 6) Turn the "T" --> "Lazy H" by attaching the lower element.
>
> 7) Tie the hoist rope to the CG point (see 2)). I used a modified double
> constrictor hitch secured by two hose clamps on both sides just in case it
> wants to slip along the boom (It doesn't if you have worked the knot up well
> enough. Heave the lazy H up so the knot is just above the tower top.
>
> 8) Awaken the lazy H by rotating it in vertical plane. If the reflector
> tip does not clear the lower guys, tilt the boom away from the tower and dance
> the boom around the mast. Now, here's a CATCH! The elements of a full size 40
> are so heavy that they will turn themselves to UNDER the boom and you can not
> hold them by grabbing the boom, if at all. We could not do it, and we could not
> turn the antenna around using two BIG plumber's wrenches. So let the elements
> go where they want to go! The elements must have been attached between the
> tower and the boom to achieve this or else they hit the upper guys from below.
>
> 9) Attach the boom truss. Lower the by now flat H to the mast plate, adjust the
> boom truss as needed. Attach the boom to the mast plate.
>
> 10) Add the missing element.
>
> **0) In fact I built a wooden scale model of the tower complete with the
> guy rings, and wire models of two JP2000 tribanders and a 3el40.
> And good I did, discovered a lot :-)
>
> **1) The ground crew MUST NOT be located near the tower. A wrench handle
> accidentally fell out of my pocket while at tower top, and landed upright
> four inches deep in hard ice. The ground crew was instructed but this unwanted
> illustration sure helped to drive the warnings home!
>
> **2) We used only the top pulley, but two pulleys are probably safer.
>
> **3) Be slow. Big antennas are hard to stop once they go fast.
>
> **4) The tribanders were raised in one piece propelling them around the
> guys.
>
> Christmas quiz: how do you get the upper three antennas in place?
>
> Seasons greetings!
> --
> Juhan ES5QX
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
More information about the TowerTalk
mailing list