THE DILEMMA OF CLIMBING AM RADIO TOWERS

[Maple2]

Hi Gurus,

Climbing a de-energized AM tower still poses a safety Hazard, as a colleague of mine found out recently. He got zapped by a Guye wire supports of a 'de-energized' AM tower he was climbing. Probably static charges due to the effects of coupling from another AM tower in operation nearby, I supposed.

Unlike Cell towers, the Guye wires (those at the top)supports of AM towers do not have direct path to ground to discharge static electricity. What is the safest way to discharge Guye wires at the top of AM towers before climbing? Thanks

 

[TugboatEng]

With helicopters, the helicopter clamps on to the wire or the boat below clamps on to the hoist cable to equalize potential before anybody touches anything.

Perhaps your buddy needs one of these:

https://www.midwestunlimited.com/all-industries/d-o-t-and-safety/jobsite-safety/monitors-1068-0.html

 

[itsmoked]

That's not as easy to solve as would be nice. If it's air driven static it's unclear on how fast it returns to a jolting level of charge. Likely pretty quickly in much wind. This is the same problem as helicopters landing on ships have. They touch the chopper with a grounding rod then clip a grounding strap on.

Here you would need to ground the guy to the tower as the tower is what the climber is referenced to. The problem is this will require a ground clip for each and every guy that the climber has to associate with. That said, they probably don't need to be very heavy other than they need to be large enough to clamp to the guys. If the climber can hug a guy thereby avoiding the other two they could get away with 3 or 4 grounding leads.

Two issues. If the towers have no bare metal there won't be a good way to clamp onto them.
If the tower is not actually grounded then tying a bunch of static charge generators (the guys) to it could result in a flash-over into the radio equipment. (I find it hard to believe the tower would be floated but I'm not sure.)

If the tower has no bare metal the only alternative is to ground the guys at the ground. to keep the hiking minimized pick the side the climber will go up and clip grounding jumpers between the bottom of the guys and the anchor stanchions.

All this aside as far as I know all guys are supposed to be grounded due to lightning issues. They sell guy grounding kits that include 10 foot bronze ground rods and all the hardware. Could well be your friend came across a rare ungrounded guy who's ground lead has failed or been burnt off by lightning or ignorantly been left ungrounded. Alternatively, he should probably refuse to climb a tower with ungrounded guys as it's an avoidable hazard. Carry with him a couple of grounding kits and charge for the installation doing that prior to climbing.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[TugboatEng]

High EMF can also generate voltage and OP mentioned other towers in the area. That's why I was looking at the EMF meter. Maybe the other tower also needs to be secured.

 

[bacon4life]

From the photo, this tower looks similar to how power poles in my region have an insulating rods in series with the guy wires. Typically workers would not reach past the insulating rod to touch the lower portion of the guy wire. If there are multiple circuits on a pole, there will be insulating rods between each level such that if the guy wire breaks, the circuits would not be connected. Other regions follow the opposite approach, and require guy wires to be fully grounded. Both approaches have dangerous failure modes.

"Static electricity" probably is not right term for voltages cause by other antennas or nearby power lines. For voltages induced by nearby EMF sources, it could be important to consider the amount of current that will flow through the grounding jumper, and the length of arc that may be drawn when disconnecting the grounding jumper. When grounding de-energized power lines, having multiple grounds can cause many amperes of current to flow. I do not know if similar high currents could be induced on de-energized AM towers.

 

[FacEngrPE]

Sometimes the guys are split into more than 1 section, when that is the case grounding on the lower end of the guy will not discharge the upper end. As stated in the post above grounding does nothing for voltages resulting from resonant coupling from a live transmitter or power lines.
Example, the white knobs on the guys are insulators.