2 meter Repeater Antenna Removal, Repair, Re-installation. 
Oct, 2015




The problem - bent mounting mast and loose coax harness.
Gin pole details.

Gin pole installed on antenna mounting arms.  Firm clamps top and bottom.
The 'C' clamp is a movable 'stop' while the pole is slipped up or down.
Antenna on its way down


Taping down the harness.  Re-orienting the lobes for omni-directional.
Antenna re-installed.  Gin pole removed.

       One of the key steps in the safe lowering of our damaged antenna & re-raising of the refurbished antenna via a gin pole was to establish a haul rope “pull” which is aligned ALONG  the axis of the antenna so that the antenna rode downward & back upward in a vertical configuration. No twisting or torquing or turning in a manner which might make it unmanageable. The ”haul line” needs to be rigged so that the bulk of the weight of the entire antenna is LOW, enabling gravity to maintain the antenna in a vertical configuration as it travels. If the antenna is left free to twist or turn in its’ travel, you have trouble.

 We calculated that IF we could establish an initial connection point via a strong welded stainless steel ring at the 2d antenna bow, we could maintain the bulk of the weight on the antenna rig BELOW that point, permitting the antenna to ride down & back up vertically, in a stable manner.
We began by using a long, light bamboo push-pull pole to “drop” a light, weighted “messenger line” over the 2d antenna bow. This line then dropped down to a level where we could reach out & pull it in. We then attached a stronger Dacron cord (about 400 lb test) and then “slid” this cord up & over the antenna bow. We then configured & slowly, pushed & pulled this cord assembly up to cinch it tight on the 2d loop. It cinched tight there, on the antenna. This stainless steel ring carried with it (as it rose) another light “messenger line”. Once in place, we used this 2d messenger line to pull up the full-sized (3/8”) haul line, pulling it through the ring & back down to our level. We then secured this

heavier final haul line (running through the ring, above) to the bottom of the damaged antenna. This gave us a FINAL haul line that ran from the top of the gin pole, down thru the stainless steel ring, to a final securing point at the bottom of the antenna. When tensioned by the ground crew, the “pull” of the haul rope now ran down from the gin pole (the top of which was above the level of the loop & ring), through that ring and down to a final attachment point at the bottom. This placed the center-of-gravity of the entire rig low, below these attachment points & insured the antenna would ride down (and back up) vertically. No twisting, spinning, flipping. A lighter “tag line” attached to the bottom of the lowering rig enabled the ground crew to pull the antenna free of any entanglements as it rode down & back up.
Sounds complex, perhaps, But these steps are critical, for safety !!!!! Rig once, check twice, then execute. You need to rig so that the tension runs straight up & down allowing the gin pole to control the lowering & raising of the weight in a nearly completely vertical manner. No twisting, no torque, limited sideward pull. It took these steps to achieve this.

 When we raised the repaired antenna back upward, we DID attach a permanent stainless steel ring at this critical point on the antenna with a residual “messenger line left in-place, dangling down, on the restored antenna. Now, should another repair project become necessary, the procedure can be executed much more easily.
These steps are critical. Before you loosen or free the antenna from its’ mounts, you need to insure that it will ride up & down vertically without dangerous twisting, flipping, torquing. A strong, vertical gin pole rigged with a haul line & tag line as described above sufficed, for us, to lower & re-raise a 60+ lb antenna.