March 2019
« Jan    



Engineer Killer

That was the title of the email with this photo attached:

Disabled high voltage shorting bar, Collins 820D-2

Disabled high voltage shorting bar, Collins 820D-2 AM transmitter.  Courtesy Pete Partinio

Seems about right.

For many, many reasons, this is a bad thing to do.  First of all, that shorting bar is the last point of discharge for the high voltage power supply.  When all else fails, this is designed to route the 3,500 volt plate supply safely to ground.  Having a stray 3,500 volts floating around inside of a transmitter is never a good idea.  Fortunately, it was spotted and removed before anything bad happened.

Secondly, it looks like somebody used a 12 VDC cigarette lighter plug as an insulating device.  Wow, did they get lucky.  This could have started a fire.

As to exactly why it was there in the first place, I cannot rightly say.

And this is why only properly trained people should be working on transmitter, especially tube type transmitters.

Man electrocuted putting up a pirate radio antenna

A south Florida man was electrocuted when the antenna he was putting up struck a power line. Police say 42 year old Jean Adelphonse was working in the dark Monday night when part of an antenna to be used for an unlicensed radio station collapsed and struck a power line.  The Fort Lauderdale Sun Sentinel reported that he was working on the roof of an office building where his other businesses were located.

That is rather unfortunate and completely preventable.  The first red flag here is working in the dark.  The second would be working alone.  Safety is always paramount; whether it is working on a transmitter, putting up an antenna, working on a ladder, environmental conditions such as heat, weather, etc.  In my younger days, I had gotten away with a few careless moments mainly due to blind luck.  I cringe thinking about it today.  Nothing in radio is worth killing yourself or anyone else over.

This type of thing used to happen more often when almost every house had an outside TV antenna.

Let’s be careful out there.

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.

OET65? What is that?

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:

WER radio, 192X?

WER radio, 192X?

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.

Tower Safety Equipment

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:

Western Electric 200 foot tower with retro fitted safety climb[

Western Electric 200 foot tower with retro fitted safety climb

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.

Tower safety climb

Tower safety climb, attached to climbing ladder

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.

Protective gear and worker safety

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:

improperly attired worker attempting unsafe operation

improperly attired worker attempting unsafe operation

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:

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. Generators and backup power.  Generators pose several hazards; fuel and batteries can be explosion risks, revolving parts, thermal burns and high voltage.
  8. 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.


A pessimist sees the glass as half empty. An optimist sees the glass as half full. The engineer sees the glass as twice the size it needs to be.

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
~1st amendment to the United States Constitution

Any society that would give up a little liberty to gain a little security will deserve neither and lose both.
~Benjamin Franklin

The individual has always had to struggle to keep from being overwhelmed by the tribe. To be your own man is hard business. If you try it, you will be lonely often, and sometimes frightened. But no price is too high to pay for the privilege of owning yourself.
~Rudyard Kipling

Everyone has the right to freedom of opinion and expression; this right includes the freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers
~Universal Declaration Of Human Rights, Article 19 was discovered, and not invented, and that these frequencies and principles were always in existence long before man was aware of them. Therefore, no one owns them. They are there as free as sunlight, which is a higher frequency form of the same energy.
~Alan Weiner

Free counters!