Readers of this blog will know that I enjoy history. Old photos are great things to study, as they say, picture… thousand words… etc. Here is one that I found on the RadioMarine website:
Here we have three gentlemen at work at an early radio station. It seems like a posed shot, nobody can study a meter that intently. They are sitting directly in front of the transmitter and it looks like the antenna tuning coils are behind the operating position. Notice the open wire and transmission line, presumably all under power when this picture was taken. There seems to be no concern about RF or electrical safety, I suppose it was trial and error back then, with a heavy price paid for error. Meter boy should be careful not to back up too far, if he does, he’ll get a little behind in his work.
We’ve been a little busy this last week, I’ll catch up on the blogging this weekend, there are many things to tell.
The tower climbing video that has gone near viral pointed out a few things. Climbing towers is dangerous business, best left to those who are trained for it and have the insurance.
It is true that tower climbing contractors have the responsibility to protect their own workers while working on a clients tower. That does not completely absolve the tower owner from liability. The it is incumbent on the tower owner to provide a safe structure to climb. This can mean the mechanical integrity of the tower, reduction of transmitter power while workers are in high RF energy fields, and providing the proper permanently attached safety equipment on the tower itself; Climbing ladders, ladder safety cages, rungs, elevators, and fall arresting gear.
In that tower video post, I mentioned something called a safety climb. That is a cable, usually 3/8 inch stainless steel aircraft cable, attached, about eight inches from the climbing surface like this:
The tower itself was built in 1959 and did not have this equipment when new. This was a retro fit kit, installed in 2003, I believe.
The tower climber wears a harness with a special karabiner attached to the front and waist level. When climbing this ladder, the karabiner slides up the cable. If he were to fall, the karabiner has an auto locking or braking mechanism that would stop his fall.
Many tower climbers, especially those that have been in the business for a while, do not like these things. When climbing, especially if one has long legs, the tendency is to bump your knees on the bottom of the next ladder rung. This is because the belt holds the climber’s waist in making it difficult to get the rear end out, away from the ladder the way most people like to climb. The alternative is to climb with the knees spread apart, like a frog, which is hard on the hamstrings and quite literally, a pain in the ass. However, if a tower is so equipped, it must be used.
I have, wherever possible, retro fitted towers with these devices. Of course, all new towers come equipped with them. In some situations, it is not possible to retro fit towers with safety climbs, either because there is no attachment point at the top of the tower that meets the OHSA spec, there is not a climbing ladder, or it would affect the tower tuning, as in an AM tower or near a TV or FM antenna.
Hundreds of gallons of ink have been spilled by Los Federals in OHSA regulations 29 CFR 1926 and 29 CFR 1910.268(g) regarding fall protection and fall protection equipment for telecommunications workers. In this litigious world we live in, tower owners and or their on site representatives should know these rules and make sure they are followed.
Safety at work is one of those things that is often overlooked for various reasons. Sometimes we just get into a groove and are not thinking about it. Other times, employers can put workers in a potentially dangerous situation by ignoring regulations or insisting employees do things contrary to common sense.
For a broadcast engineer working in the field, safety can be a matter of life and death. Transmitters, in particular, have a host of potential safety issues; high voltage, thermal burns, RF burns, revolving mechanical parts, and external things like lightning. Transmitter sites themselves can be critter magnets, anything from bees to raccoons, bears, and even the two legged kind.
Good general practices can go a great way in reducing injuries and downtime. Take this young fellow here:
First of all, it appears he has gone to work in his pajamas, which is a no-no. Secondly, he has the right idea, wearing safety goggles while undertaking the risky operation of cutting low density polyethylene with a pair of hand shears, however, those look more like swim goggles. They appear to be improperly donned. He is using a right handed shearing device with his left hand and the work area looks cluttered and unkempt.
Seriously, we are all responsible for ourselves. While at work, it is important to use common sense. I may be a wimp, but if I have a question on whether the breaker is on or off, I go check. High voltage power supplies offer no second chances. Here is a list of things to be cognizant of while working at transmitter sites:
Weather. If the transmitter got knocked off the air by lightning, wait till the storm is over to fix it. It is still coupled to the tower, even if the backup transmitter is on the air.
Fall hazards. OHSA requires fall protection for any worker working at an elevation higher than 4 feet. Fall protection can vary CFR 29 subpart E 1926 has all the details.
Falling object hazards. Tower works have been known to drop a wrench from time to time. A hard hat should be required whenever climbers are on the tower. Also, I watched ice shedding from a 1000 foot TV tower practically destroy a fuel delivery truck in a matter of minutes.
RF safety. I require all tower climbers to wear personal RF alarms when climbing on any tower that has RF radiators active. Do not work in hot ATU’s or Phasors. ATU’s and Phasors should have provisions to make all necessary measurements with protective covers in place and minimally exposed RF parts.
Electrical safety. Never work alone at a transmitter site. Turn off breakers before opening transmitter doors, do not defeat interlocks, always discharge high voltage with ground stick. Hang ground stick on HV power supply output. Tag out breakers if in a separate room from transmitter.
Critters. Use bee spray on ATU’s and other outdoor structures. Be careful around wild animals, even mice and mice dropping can spread disease, use hand cleaner after cleaning up mice nests. Snakes love tuning houses, generator sheds or just about any building that is not inhabited.
Generators and backup power. Generators pose several hazards; fuel and batteries can be explosion risks, revolving parts, thermal burns and high voltage.
Access to site. Some areas where mountain top transmitter sites are common, access during winter months can be tricky.
Much of this is common sense, remember, a radio station is a radio station, there is only one you.