The BE STX 10

We just finished installing one of these units on Mount Beacon for WSPK. Mount Beacon is around 1,500 feet high and is accessed by a road which is a little bit rough. After the snow flies, the only way to get there is a snow machine or perhaps a helicopter. Thus, whatever is installed there needs to be reliable.

BE STX 10 mounted in Middle Atlantic Rack, WSPK, Mount Beacon, NY

My first comment, I recall 10 KW FM transmitters being much larger. This unit is pretty compact and we probably could have fit two of them in this Mid Atlantic rack had we wanted to.

BE STX 10 FM transmitter

The transmitter itself is pretty simple, four RF modules powered by seven OEM switching power supplies with two fan power supplies, one for each fan unit. This is driven and controlled by a STXe 500 watt exciter.

The back has a 1 5/8 inch EIA flange output, some power connections, remote control interface, etc. Pretty simple overall.

I can also say, there was a noticeable improvement in the audio quality when this was placed in service.

Resurrection of a different sort

I just finished a full alignment of my Kenwood R-2000 receiver and tonight I am treated with the pleasing tones of “Jazz from the Left,” on WRMI. Jazz from the left means the west coast sound, aka Smooth Jazz as I am given to understand. I spent some time on the west coast and beyond. I have fond memories of those years.

It is amazing to me still, that a simple AM receiver demodulating +/- 4.5 Khz audio bandwidth from 1,057 miles (1701 km) away can sound that good. That is being received directly; no Internet Service Provider, no satellite service, just a transmitter and a receiver.

There is an art to all this, which is being forgotten. A few minutes with a manual, a volt meter, a tone generator and a non-conductive screw driver can bring something that was neglected back to life sounding as good as the day it left the factory 35 years ago. Try that with with your very expensive iPhone 10,000,000x! Of course, you will need those tiny pentalobe tools to get the screws out. Apple would rather you return your expensive i device to their expensive i store so that their i geniuses can fix it for you.

I don’t know, maybe I am an old fart. Perhaps the right to repair the appliances that I purchased and therefore should own is an old fashioned point of view. After all, all of these corporations have my best interests at heart, right?

I recommend you support your not so local shortwave stations by listening and supporting their programmers. Even in 2021, there are still many shortwave broadcasts that are worth listening to!

The future of Broadcast Engineering

Nature abhors a vacuum.

There has been a lot of hand wringing and ink spilled recently on the titled subject. The problem seems to be particularly acute when it comes to RF knowledge. I agree with those concerned that there are very few new (read also as young) people entering the field. There are a number of reasons for this; competing technical fields that pay more and are generally easier to work in, the very broad knowledge base required for Broadcast Engineering, and the lack of awareness by major stake holders.

It seems obvious that for as long at there are radio and television stations, there will need to be those people who install and maintain the transmission systems. The question is, how to attract new people into that field. In order to answer that question, a follow on question would be, what exactly does a Broadcast Engineer do?

This can be broken down into three very broad areas:

  1. Conversion of the art into electronic form. In other words, capturing sound and video with cameras and microphones. What are the various analog and digital formats, how are those signals routed, edited, stored, retrieved and transmitted. What are the various bit reduction (e.g. compression) formats. How these live streams and stored files are mixed to generate the final program material.
  2. Transmission of the program material. Meaning moving the program to the transmitter site and broadcasting it for public reception. This would involve knowledge of Studio To Transmitter (STL) systems which can vary greatly but often include satellite distribution, public internet, fiber, RF wireless microwave systems, etc. Next step is the actual transmitter, filters, combiners, transmission line and antenna. Knowledge of all regulatory (in the US, FCC) obligations including EAS, Tower lighting and marking, transmitter operations; power level, interference, etc.
  3. Physical plant systems. Broadly speaking; HVAC, electrical power, emergency generators, towers, fire suppression, etc.

These work categories can be further broken down into three functions; installation, maintenance and replacement.

Since I have been more involved in the management side of things lately, I find that most of my problems are people problems. What may be a surprise to some, Broadcast Engineers are people. What may be even more shocking; people have interests. Those interests are the reason why they chose to work in a technical field. Forcing the IT guy to go to the transmitter site to see why the generator won’t start is not a good use of resources.

Looking at the very large skill set that a competent Broadcast Engineer needs to function in a modern broadcast facility, the first part of the answer becomes obvious; more specialization. Break down these broad categories into separate skill sets. Since it seems that many things are headed toward the IP domain, Broadcast IT should become a thing separate from office IT. While the two are similar, Broadcast IT requires more knowledge of physical wiring, switch architecture, VLANs, subnets, IP streaming protocols, audio formats, video formats, transport streams, etc.

RF infrastructure has its own set of rules, including personal safety requirements. A solid electronics/engineering background is required to understand how transmitters work, what various failure modes are and what can cause them.

Physical plant work, most often can be contracted out to various vendors. However, that work needs to be supervised by a competent station representative.

The next item is the thing that nobody wants to talk about; the all importance of work/life balance. This means not utilizing a broadcast engineer as a piece of equipment to be worn out and discarded when the performance level drops below expectations. I have know several broadcast engineers who have left the industry because of this. Worse still, there are those who have died of heart attacks or committed suicide. Work/life balance also includes proper compensation, so those people can afford to pay for essentials, have a reliable vehicle, healthcare, etc.

Of course, many smaller operators cannot afford to hire a RF specialist and a Broadcast IT specialist plus pay contractors to do physical plant maintenance. This is where contracting can fill in the vacuum. If contracting becomes the new normal, then how does the next generation of Broadcast Engineers get trained? Broadcast transmitter manufacturers have some training courses available as does the SBE. However, there is no substitute for hands on experience. While many Broadcast Engineering evolutions are similar, no two situations are the same and thinking on your feet is a job requirement. How are new people coming into the field get the necessary experience? The situation is not untenable, however it will require some creative thought.

The GatesAir FLX-30

This is the second time I have installed one of these liquid cooled transmitters. This time, it is for WVPS in Burlington, VT. WVPS is the flagship station for Vermont Public Radio. The station is a full class C, a rarity in the North East. The transmitter is located on Mount Mansfield giving it a HAAT of 2,717 feet (828 Meters), which is a good ways up.

GatesAir FLX-30, WVPS Burlington, VT

This transmitter replaced the previous backup transmitter, a Harris Z16 unit from the early 00’s. There was nothing really wrong with this unit, it just was not a full power backup.

Harris Z16 transmitter

The new transmitter came in two pieces, which is typical for the 30 and 40 KW GatesAir liquid and air cooled transmitters.

New Transmitter, being placed in Radio Transmitter room

For the cooling part of this installation, 1 1/2 inch type M copper pipe was used. This matches most of the other TV transmitters down the hall. In the same building are the transmitters for WCAX-TV, WPTZ-TV, WFFF-TV, and WVNY-TV.

FLX-30 Heat Exchanger, outside with all the others
Liquid cooled transmitter piping, WCAX’s left pair, WVPS right pair
Air purge valve, sight glass, cross connect and distribution manifold, above the transmitter

The highest point in the liquid cooled system is the air purge valve and distribution manifold just above the transmitter. From here, everything slops down to a few low points; the heat exchanger outside, the pump station and the power blocks. This is to make it easier to drain, if that ever needs to happen. There is also an air inlet valve to aid in draining.

GatesAir pump station

All of the cooling work is controlled by the pump station. The fans are connected to VFD modules, which control the flow of air though the Heat Exchanger.

Milwaukee Press Tool

All of this plumbing work was greatly sped along with the use of this Pro Press pipe press tool. This thing is great! No more sweating connections. Dry fit a section to make sure that it is all cut correctly, then go to work with this and it is done in a matter of seconds. Of course, there are no re-dos, so the dry fit procedure is a little more important.

System flush and pressure test

Prior to filling with with Heat Transfer Fluid (50/50 water/antifreeze mix), the system was first pressure tested with air, then filled with clean water for a 12 hour flush. The water was drained out and the filter screen cleaned, then it was filled with the appropriate Heat Transfer Fluid.

Testing into dummy load, TPO is 25,995 watts with -14 dBc HD Radio

Final system checks, remote control test, and HTF top off and the transmitter is ready to go pending the HD Radio installation.

WEZF and WVPS four bay three around panel antenna