Survival of the fittest
Site hardening is a regular practice for two-way radio operators. Faced with threats from the environment and humans, these operators take proactive steps to protect their towers, transmitters and transmission wires. The steps include enclosing the site with razor wire-topped wire mesh; eliminating glass windows and non-metal entrances; and keeping grass and brush trimmed to minimize wildfire damage.
These are sensible precautions that do make a difference. However, there are still extreme threats to be dealt with — both natural and manmade. For that reason, many site owners practice "extreme" site-hardening, where common precautions such as those described above are taken to the next level. You may not be able to stop an earthquake from toppling your tower or a vandal in a stolen 18-wheeler from plowing through your fence, but you should be able to stop nearly everything else.
When it comes to natural disasters like tornadoes or hurricanes, "it is usually the towers that stay standing while everything else falls," said Jim Coleman, president of Southern Broadcast Services in Pelham, Ala., and chairman of the National Association of Tower Erectors (NATE). "This isn't surprising. Towers are built to such rigorous standards, that they have the necessary strength built in to survive the worst that weather can throw at them."
While tower anchors and bases are vulnerable to human damage, this threat can be reduced substantially by encasing these areas in heavy steel, which blocks access and thus prevents vital cables from being cut.
Also vulnerable to damage are the transmitter buildings installed on two-way radio sites — unless they are designed to stand up to abuse. This is why modern transmitter buildings tend to be made of reinforced, precast concrete. "These structures are really tough,' said Jeff Hahn, president of Global Tower Service in Woodland, Wash. "They can stand up to a passing hunter who can't resist taking a potshot at the building. Typically, concrete transmitter buildings measure 12 feet by 20 feet, weigh 60,000 to 80,000 pounds, and have to be lowered onto their concrete pads by a heavy-duty crane. Add thick steel doors and enclose your cables in rigid PVC, and nobody is going to hurt this monster."
For two-way radio operators who want their site hardening to be really extreme, there's the SubTerra controlled environmental vault from Powerwave Technologies. This is a reinforced, watertight 13-foot by 13-foot by 6-foot tall fiberglass vault that is buried below grade. All that is seen above ground is a flat surface, which can be disguised to look like a concrete slab with a park bench on top.
Whenever technicians need to access the equipment inside the SubTerra, they just activated the unit's built-in hydraulic elevator: It lifts the entire transmitter platform above ground for easy servicing. (A rain shelter for inclement weather is included with the SubTerra systems.)
"The SubTerra doesn't have the potential for leaking that a buried concrete vault has, because it doesn't have seams" said Jake MacLeod, executive vice president of Powerwave's government solutions business unit. "Meanwhile, the top is gasketed to prevent any water from coming in from above. We've even had our SubTerras covered by feet of floodwater. Once the water was gone, we've opened them up and found them to be bone dry."
One other solution to flooding "is to build the transmitter building on a scaffold, so that it sits above the flood plain," Coleman said. Add fencing and razor wire around the legs, and you've got a secure site — as long as it can stand up to the weather and errant bullets. "There always seems to be some kid with a gun taking shots at something," Hahn said.
Some people break into transmitter sites to cause damage for its own sake. But others are looking for things to steal, and it's not always copper wire. "We work on a lot of mountaintop transmitter sites, and one thing thieves go after are the electric meters," Hahn said. "They use them in their marijuana 'grow ops', to hide how much power they are using. They stick the stolen meter in until someone is due to read the meter. They put the original meter in, have it read, and then put the stolen meter back."
Nevertheless, copper wire remains a prime target for thieves. As a result, "some copper wire manufacturers are coating them with a resin that makes them hard to recycle," Coleman said. However, given that most thieves are not up on industry practices, it is probably wise to follow Hahn's lead and encase valuable copper in PVC pipes. "This disguises the wire, and also provides a layer of protection to make it harder to cut," he said.
As the old cliché says, a chain is only as strong as its weakest link. In a fenced enclosure, the locked gate typically is the easiest place to break through. "The U-bolts that hold the gate hinge to the post is typically a weak spot that can be moved, bent or broken," Hahn said. "So I tend to tack-weld mine in place, to make them immovable and stronger."
When in doubt, highly visible security cameras with glowing red LEDs can deter some thieves — even if the cameras themselves aren't connected to anything. "Realistic-looking fake security cameras work as well as the real ones when it comes to scaring off vandals," Hahn said. "You just have to remember to keep their batteries fresh, so that the LEDs don't fail."
As noted at the start of this article, it is impossible to protect a transmitter site from every eventuality. This is why two-way site operators need to be prepared for trouble, said Jack Boone, vice president of Broadcast Tower Technologies in Sarasota, Fla. "Things happen, like when someone shot holes in one of our 1,400-foot antennas during deer hunting season," he said. "We had to get up there fast to patch those holes, to get the antenna working properly again. Fortunately, we are set up to respond quickly. As a site operator, you have to be able to respond quickly, too; either yourself or by using a third-party technician who is available 24/7."
Fast response is the last line of defense in the extreme site-hardening arsenal: When all else fails, you have to get to the site and do what needs to be done. But with any luck, you won't have to do this as often, thanks to extreme site-hardening. That's because your equipment and installations will be able to take most of what nature and humans throw at it — and survive.
James Careless is a freelance writer.