[TowerTalk] Personal tram tips

[Jim White, K4OJ]

When suspending an antenna from a tram line usually the biggest hassle 
for me has been that when you get to the top the antenna is "trapped" 
under the tram line which often is NOT on the mast above the target area.

To overcome this you have to be able to undo the tram line before that 
final lift vertically of the antenna.

By using a gin pole as the pulley at the top of the line that pulls the 
antenna up the tram you can also use it to act as the booster to get the 
antenna to its destination.

The critical thing to watch for though is NOT to have the gin pole 
extended much above the clamp as you are putting horizontal pull on the 
gin pole... this is not what it is designed for... so... if the top of 
the gin pole is low it is not much help as far as the final boost.

When the antenna gets to the top of the tram, I usually have a short 
rope with a snap ring on it that runs from the boom near the tram point. 
  Snap the ring onto a tower rung when the beam gets to the top of the 
tram and then let the pull rope go slack so the antenna travels back 
down the tram until that short rope becomes taught.

With the beam restrained, you can now raise up the gin pole so its head 
is above the point on the mast where the beam attaches.

Also, you can now instruct the ground crew to make the tram line come 
slack... I usually use my pickup truck as the ground end of the tram, as 
this means adjusting its tension is simply forward or reverse (gingerly) 
travel by the truck.  So, slowly back the truck up a few feet and the 
beam will swing into the side of the tower as the tram loses its tension.

I use a clevis at the top of the tram line where it attaches to the 
tower or mast - the end of my tram line has a permanent eye on it and 
once it is slack, it is easy to undo by removing the pin of the clevis.

Use a snap ring to hook that end onto a tower rung below the beam just 
in case it is necessary to resurrect the tram and bring the beam back down.

Re-attach the gin pole rope to the beam and have the ground crew give 
the beam that last boost up to its installation destination.

As K7LXC noted, unlike traditional building the antenna up on top, most 
of the work is installing the tram system.  Being able to send a 
finished antenna up is worth this work. You can do a better job of 
leveling the elements, tightening the bolts and general assembly when 
you are working at ground level than you can in the air.

By good prep work ahead of time, the coax can be ready to go, and within 
minutes you can be busting pileups (hopefully!)

Of the ten yagis for 10 through 40 meters in the air now at the station, 
only one of the small 4 element beams was NOT trammed or trolleyed up... 
A tram system is a good investment... buy a spool of wire rope and put 
an eye on the end of it.. set it aside in the garage and use it when it 
is beam time... you will be glad you did!

73, Season's

Jim, K4OJ



K7LXC at aol.com wrote:

> In a message dated 12/18/03 8:45:28 PM Pacific Standard Time, 
> gjerning at flash.net writes:
> 
> 
>>Nice pictures of a 2 wire tram system.  
> 
> 
>     A two-wire system where the load is slid up while sitting on top of them 
> should more properly be called a trolley system; i.e. a trolley car that sits 
> on top of two tracks.
> 
> 
>> I used a single wire tram which is easier to rig.  
> 
> 
>     This is a more useful antenna raising system where the load is suspended 
> below the single tramline. The haul line from the ground goes through a 
> snatchblock (a pulley that opens on one side to accept a rope) at the bottom of the 
> tower so that the groundcrew can stand away from the tower and pull 
> horizontally while watching the load. The rope goes up to another pulley at the top of 
> the tower and then down to the ground where it attaches to the load. Another 
> pulley is attached to the tramline, load, and haul rope. When you've got 
> sufficient tension on the tramline, then the groundcrew can start pulling the haul 
> line and raising the antenna. 
> 
>     There are a number of tricky issues that you sort of have to address by 
> trial and error; i.e. rigging the antenna, using as compact of a knot and 
> rigging as possible, where to attach the pulley to the mast, how much tension to 
> use, etc. It's one of those things that takes 2 hours to rig and then 10 minutes 
> to do the job. I use it about 90% of the time when installing antennas 
> manually. 
> 
> Cheers,
> Steve     K7LXC
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