LINKS: TOWER TRAM ANTENNA VIEWS
Answer: Helicopter (Expensive), Crane (No Access), Tram (Never tried it but always a first time)
The tramming system is comprised of the following, the top mount, the bottom mount, the tram wires & hoist rope, and the tram itself. First a four foot long piece of steel channel is mounted to the top of the mast (need strong mast for this). The tram wires (Phillystran in this case) attach to each end of the channel and are run down to the hoisting area (located at least 1.5 the height of the tower away). A block is attached to the center of the channel at the mast; the hoist rope extends down to the ground and the other end out to the hoist area. The two tram wires attach to come alongs which in turn are attached to a vehicle which can be moved away from the tower. The tram itself is a square steel angle iron frame with pulleys on all four corners. Two u-bolts are located in the top cross member near those two pulleys and another u-bolt in the center of that member. The tram hangs under the tram wires by the pulleys. The antenna boom is attached to the two outer-mos!
t u-bolts and is under the tram and the hoist rope to the middle u-bolt. The antenna goes up level (kind of) and sideways.
Once all is set and the hoist crew has taken up slack in the hoist rope, the vehicle is slowly driven away from the tower and the antenna raises up along with the wires. Now the hoist crew begins to pull the antenna up the wires like a cable car going up the side of a mountain. The come alongs are used to maintain the antenna level as it goes up. We had a problem from the start in that the balance point was right at the driven element and the antenna wanted to flip as it went up. Down it came. Not wanting to move the element (minimize the up the tower work whenever possible) we attached barbell weights to the boom to balance the system. Notice the two round orange disks in the pictures. Up she went in about 10 minutes total time.
Once up picture the following. The antenna hangs under the tram frame which is under the tram wires. The tram wires are slacked which allows the tram and antenna to swing vertically with the antenna boom up against the mast. Then the hoist rope is slacked which allows the antenna to drop down along the mast into position on the mast plate where it is bolted on. Remove tram, drop top channel and wires & rope, and connect the feedline. Of course the wind picked up just as we were attempting to bolt the antenna to the boom to mast plate. Antenna installation, done.
Click on a small picture for larger view.
The ground level anchor for the tram. Come-alongs are used to level the tram.
Antenna ready on the tram.
Antenna starting its ride.
There she goes.
Top end of the tram.
Almost there.
Bolting the antenna to the mast.
Job well done.