Why be a Broadcast Engineer?

That question was posed to me this afternoon by a coworker.  It is, indeed, a good question.  Certainly, broadcast engineering is more of a vocation than a career, especially where it concerns radio stations.  Why would anyone work for low wages, long hours, little or no recognition, 24/7 on-call, and or unappreciative management?

Further, in this risk-averse, zero-defect, micromanaged environment, what is the upside to being a radio, RF, or broadcast engineer?

I suppose one would have to have some appreciation for history.  One of the reasons I cover radio history here or certain historical events is that without knowing the roots of radio, one would be hard-pressed to find today’s version of radio broadcasting even remotely interesting.  Understanding that before there was the internet, web streaming, Spotify, Youtube, Sirius/XM, television, cellular telephones, 3G, 4G, and so on, radio was mass media.  Radio was people-driven, and people-oriented, not an automated computer programmed from afar.  People tuned in for the music but also the personality and the personal connection.

Growing up in the late sixties and seventies, radio was my link to the outside world.  As a young boy living in rural upstate New York, my mostly agricultural surroundings seemed a bit provincial.  Through radio, I was able to listen to the clear channel stations from New York City, Chicago, Detroit, Nashville, Charlotte, Pittsburgh, Washington DC, Cincinnati, etc.  The street that I grew up on did not get cable TV until 1980, prior to that, the rooftop antenna received exactly two channels when it wasn’t blown over by a storm.  The black and white TV was often broken, sometimes for over a year.  It was of no great consequence, however, when nightly under my pillow, the battery-powered transistor radio was employed until midnight or later.

When I got older, shortwave radio kits were built and listened to.

Through that medium, I learned about life outside of my small town.

Author, sitting in front of Atwater-Kent Model 20 regenerative receiver
Author, sitting in front of Atwater-Kent Model 20 regenerative receiver

The upside is being a part of something that can still be great, although those stations are getting harder and harder to find.  Still, there is a certain pride to a job well done, a clean transmitter room, and a well-tuned machine working into a properly tuned antenna.  Does anyone even appreciate that anymore?  I do.  Lou Dickey, John Dickey, Bob Pittman, Leslie Moonves, and other CEOs may not care that the transmitter site is clean and well-kept.  They may, in fact, question it as a waste of salary.   I appreciate it. Fellow engineers will appreciate it, too.

Starting a transmitter, especially a high-powered tube transmitter, is a joy all its own.  Nothing against Nautel, they make fine transmitters, however, when pressing the on button, the outcome is almost assured: The transmitter will turn on.  Not so with certain tube-type transmitters.  Pressing the plate-on button for one of those can have many different outcomes.  There is a certain thrill when it all works right, the first time.  There is a certain pride in driving away from a transmitter site, listening to the radio, and knowing; I caused that to happen.

The 90th anniversary of…

Many of the US’s earliest commercial radio stations are celebrating their 90th anniversary of broadcasting this year.  I’ve seen announcements for WOR, WGY, and a few others.

It is fun to go back and look at the old pictures of those stations during the golden age of AM radio.  If nothing else, it reminds us of what used to be and will likely never be seen again.  Stations like WGY employed hundreds of people in their hay day; actors, musicians, announcers, news people, salespeople, support staff, engineers, etc.  These days, WGY likely employs less than ten, certainly not more than twenty directly.

There are a few stations bucking that trend, but very few.

So here is to what once was and happy birthday to the hollowed-out shells of their former selves.

The old humming console

We are starting to work at a new client’s studios.  It is a bit like stepping into a 1980s time machine, as the newest console seems to be the Broadcast Audio console in the FM studio.  I feel I should wear a wide colorful tie and part my hair in the middle when working there.  There is also an older UMC console in the second production room.

A what?

Exactly.

It seems the UMC console (UMC was a Connecticut-based console manufacturer that was later sold to Broadcast Audio) was having an intermittent hum problem on all the audio buses.

After poking around under the hood for a few minutes, I decided I should begin with the basics.  Checking the power supply for ripple seemed like as good a place to start as any.  This console has a 30-volt and a 12-volt power supply.  The 30-volt supply checked out good, but the 12-volt supply, not so much:

12 volts DC, 2.7 volts AC
12 volts DC, 2.7 volts AC
12 Volt power supply
12 Volt power supply

2.7 volts AC on the 12-volt DC power supply.  That will put some hum on the audio, all right.  I tried to replace the power supply main filter capacitor, but it had no effect.  The regulator must also be bad and it is a Motorola part number which is likely not made anymore.

12 volt linear power supply
12 volt linear power supply

This is a pretty standard off the shelf power supply, I should be able to get one from Mouser for about $60.00 or so for a linear unit, which will be cheaper than us trying to trouble shoot and repair the old one.  In the meantime, I took the 10 amp 0-30 volt bench supply and pressed it into temporary service.  The console is working again, for now.

At some point, all this old, um, stuff needs to be replaced.

The open delta three phase service

Several months ago, I drove up to an FM transmitter site, looked up at the utility pole, and saw this:

Three Phase open delta transformer bank
Three Phase open delta transformer bank

Three-phase open delta is a bad hombre.  Most, if not all, transmitter manufacturers will void the warranty of any transmitter connected to a service like this.  What is perplexing is it appears that all three phases are available on the primary side, why would this be necessary? Perhaps it was not always so at this location.  Regardless, this was the source of power for 20 KW FM transmitters since 1958 until we moved it to a new building last month.

According to a GE publication on transformers, open delta 3 phase power is undesirable because:

Although this connection delivers three-phase currents which are approximately symmetrical to a three-phase symetrical load, the currents flowing in the high voltage circuit are not equal nor are they 120 degrees apart.  The maximum safe output of the bank operating in this manner is 58% of a 3 pot Wye/Delta bank. The system is grossly unbalanced, both electrostatically and electromagnetically.

Schematically, it looks like this:

3 Phase open delta power
3 Phase open delta power

Regular 3 phase delta looks like this:

3 phase delta power
3 phase delta power

Most utility companies will not hook up 3 phase delta on the customer side anymore because the “high” or “wild” leg, which as shown in the diagram runs a good deal higher than 120 volts to neutral.  Hook up a high leg to a single phase 120 volt piece of equipment and wait for the power supply to blow up.  Also true with 277-volt lighting circuits, as my assistant once found out with the Coke Machine in the break room.  The new 3 phase service will almost invariably be 208 wye unless there is some very compelling reason, which is fine.

There are many ways to get around three phase open delta, perhaps the best is a rotary phase converter.  This piece of equipment will take a 240-volt split phase and add a third leg.  These legs will not be 120 degrees apart, as they would be in a true three-phase, however, they will be close enough that 3 phase motors and transformers will be happy.

Rotary Phase converter
Rotary Phase converter

This leads to an unbalanced voltage/current condition which needs to be accounted for in the design of the unit.  The second way to do this is to power a three-phase generator with a split-phase motor.  This will completely isolate the 3 phase equipment from the utility service and provide for true three phase power.

The downside to any motor/generator or rotary converter is moving parts and conversion inefficiencies.  At any transmitter site that uses this type of equipment, either a backup power converter or a lower power split phase backup transmitter should be installed.  With all mechanical things, eventually, this will need to be repaired and it would suck to be off the air while that is happening.

Regardless of any of that, this particular service is about to be disconnected permanently.  Good riddance.