PBS Frontline: Cell Tower Deaths

Interesting video (part 1 of 3) about the large numbers of Cell tower deaths in the last eight years:

Watch Cell Tower Deaths on PBS. See more from FRONTLINE.

There are two kinds of tower companies, those that have been around for a long time and do things right, and those that hire subcontractors who are minimally trained and take shortcuts. The reasons for this are the same and we hear them over and over again in all aspects of this business; budgetary constraints, time constraints and what, who me?

The rest of the videos can be found at PBS.org:  Frontline: Cell Tower Deaths

Written story from Propublica: In Race For Better Cell Service, Men who climb towers loose their lives.

Tower light malfunction

We were notified that the WFAS-AM tower lights were out, thus, it was time to investigate. This problem was easy to find. Upon removing the water proof cover on the tower light flasher box, I found this:

SSAC melted tower light flasher, damaged by lightning
melted SSAC B-KON tower light flasher, damaged by lightning

As soon as loosened the screws on the cover, I smelled the unmistakeable odor of burned electronics and plastic.   I disconnected the flasher and covered the photocell, which turned the side markers on.  Of course, the top flashing beacon was dark, therefore, it was time to report the outage to the FAA.  The nation wide number to report tower light outages is (877) 487-6867.  That number is for an automated system, however, eventually it leads to a live person.  Since the new reporting system was established, the only required information is the tower ASRN.  From that information, the operator will access a data base and have all the required information to issue a NOTAM.  In the past, many questions were usually asked; what is the nearest airport, how far away is the airport, how tall is the obstruction, what is the position, etc.  Therefore, things have become slightly easier than before.

Once the outage is reported and a NOTAM is issued, the tower owner generally has fifteen days to correct the problem.

Tower take down pictures

A few years ago, I was involved in removing and rebuilding an AM radio station tower in Gainesville, Florida.  The old tower was a hollow leg tower which was rusting from the inside out.  It was installed around 1960 or so, but the actual  records were sketchy, as the original studio building burned down in 1984.  In 2005, the tower climbers came out to relamp it, and refused to climb it because one of the legs was rusted through.  Therefore, a replacement tower was ordered and delivered.

Prior to starting work, a temporary wire antenna was constructed.  Since there were two radio stations diplexed to this tower, it became a bit of a chore to get both signals (980 and 1430 kHz) tuned into the same temporary antenna.  In the end, the components available could not create a good load for the 1430 station, so a separate temporary wire antenna was erected for that station.  Both stations ran at 1 KW into their respective antennas until the new tower was finished.

WDVH, 980 Gainesville, FL.  Top of tower coming down
WDVH, 980 Gainesville, FL. Top of tower coming down

Top section of a 240 foot guyed tower on its way to the ground. This tower had an inner and outer set of guy anchor points. The top section came down after the last guy wire on the outer anchor was cut.

Remains of WDVH tower
Remains of WDVH tower

Truncated tower.

Last section of WDVH tower falling
Last section of WDVH tower falling

Bottom section of tower on its way to the ground.

Old WDVH tower on the ground
Old WDVH tower on the ground

Tower on the ground. In keeping with the theories on tower failures, this tower fell within about 1/3 its height.  The wire antenna supports and the new tower sections can be seen in the background.  It took the tower company about a week to stack the new tower.  This was done in July, therefore the average daytime temperature was about 100° F  (37° C) with frequent afternoon thunderstorms.

Do radio transmitters have the capability of electrocuting copper thieves?

I found that question while perusing my search engine statistics today.  The short answer in theory is yes.  If you are a copper thief, it will most likely look like this:

That being the case, however, it is much more likely that an RF burn will result if one comes in contact with an energized antenna or transmission line.  Even small RF burns are painful, large ones can be nasty things.  RF burns occur because of the skin effect, that is to say, the higher the frequency of the AC waveform, the closer to the surface of any given conductor the current will flow.  It is the reason why five watt STL transmitters on 950 MHz use 7/8 or 1 5/8 inch cable to reduce losses.

When a human body part comes in contact with an energized RF antenna, the body part becomes part of the circuit, thus it follows the same principals.  The extremity that is making contact will have its skin burned off.  It also smells bad.

Getting an RF burn is a painful lesson on what not to come in contact with around a transmitter site.  But, that is not all.  Simply being in close proximity to radiating elements of antennas will induce body tissue heating, just like a microwave oven.  This can lead to all sorts of short term and long term damage to organs and other problems.

Therefore, the best thing is to avoid radio and cellular towers if you do not know what you are doing.   Stay out of fenced in areas around tower bases.  No matter how tempting that copper may look, you could be seriously injured or killed if you cut the wrong thing.