[TowerTalk] Single Line Tram System - Ideas Please

[K8RI on TowerTalk]

----- Original Message ----- 
From: <K7LXC at aol.com>
To: <towertalk at contesting.com>; <k0wa at swbell.net>
Sent: Sunday, October 22, 2006 10:26 AM
Subject: Re: [TowerTalk] Single Line Tram System - Ideas Please


>
> In a message dated 10/18/2006 12:51:57 P.M. Pacific Daylight Time,
> towertalk-request at contesting.com writes:
>
>>  I have built a single line tram to lower my TH6DXX from  60 feet and 
>> raise
> a new Force-12 C3E/D.  The tram consists of a 4 foot  length of 1 1/2 inch
> PVC pipe.  Across one end I attached a 3 foot piece  angle iron using a 
> muffler
> clamp at a right angel to the pipe.  Also, I  used some angle iron (it is 
> the
> stuff you use to install garage doors) from  the from the tips of the 3 
> foot
> piece to the back of the PVC Pipe.  The  PVC pipe acts as a tiller...while 
> the
> cross piece of angle iron acts as a seat  to the boom of the antenna.
>
>>   The troubling part  of this is the single line.  I've seen double line
> tram systems but I  just don't have the room to do that.  City lot stuff. 
> So,
> using a  single tram the issue is that the antenna could roll if it out of
> balance.  Obviously, balance is very important here.

Single line should be easy to use. I use a single cable/wire rope with a 
pully riding on it. The beam hangs under the cable with the pully hook on 
one of the boom to mast clamp U-bolts.

I've not found balance to be much of a problem even if the antenna tipped 90 
degrees but each situation can be different.

As I mentioned earlier I run the "pull rope" from the boom to mast clamp out 
the nearest element toward the top of the tower.  I loop the rope around the 
end of the element forming a half hitch which keeps the element lined up 
with the tram cable and pointed toward the top of the tower.   Tipping of 
the antenna has not caused any problems for me, but to eleminate that I'd 
just loop a length of 1/8" nylon rope around each end of the boom at the 
element with some one on the ground holding each rope (requiring two 
gophers) so they can keep the bean level.

Remember to run the beam up with the boom to mast U-bolts on the "up hill" 
side so they are pointed at the mast. I attach the tram anchor to the mast 
about two feet above the top of the tower.  There should be enough slack 
from the pulley to the antenna that the antenna can be pulled forward and 
the U-bolts fastened around the tower.
>
>>  What I did is used a piece of rope connected under the cross  arm tha
> carries the boom up and hung some wieght below the tram to keep it 
> balanced.  The
> more weight ...the more stable it should be ... but that  comes at a cost.

I do not use any extra weight for balance. At most it's just the two nylon 
lines.

> The weight is fixed on the rope to keep the whole tram  in balance....but 
> that
> doesn't mean I can sloppily put the boom on the tram  without taking into
> account balancing the antenna.

There should be no need to go through all this. Just hook the boom to mast 
clamp to the pully hanging from the tramline. Balance is not normally a 
problem unless space is severely limited or there are some nearby obsticales 
such as trees.

>
>>  The whole mess has to go up to the tower and will travel less  than 150
> feet.
>
>
> "Mess" is one way to look at it. Let me clarify  a couple of things on 
> this
> topic. A TRAM system is one in which the load is  suspended below a single
> tramline. A TROLLEY system uses 2 wires (or tracks  like a trolley car) 
> where the
> load rides on top of the wire/tracks.
>
> The tram system is so simple and only uses one  cable for antenna
> installation where the trolley system is a big PITA to rig,  very 
> difficult to keep the

Amen!

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com (Use return address from home page)