Radio Guide; The Magazine

As some of you may have noticed, recently I have been writing some articles for Radio Guide. There are several good reasons for this, but the most important one is education. I believe that terrestrial radio will be around for a few more years. As others have noted, there are fewer and fewer broadcast engineers. Those that understand high power RF and all its intricacies are fewer still. It is important that a cadre of knowledgeable broadcast engineers carry on.

The internet is a great thing. However, it depends on cables of some type to exist. As we know, cables can be damaged. In addition to cables there are routers, core switches, servers and so on. All of that equipment can fail for various reasons. People have been working hard to improve the resiliency of the internet. That is a good cause, to be sure. However small it may be, there is still a chance that the internet can fail. Worse still, this can happen during some type of natural disaster or other emergency. Thus, during such an emergency, Radio can and will function as a vital information source provided that the station is on the air and has a program feed. That is also a good reason to keep the current RF STL paths in place as much as possible.

The Radio Guide articles are a great way to pass along some of that hard earned experience to others. I also want to put supplemental information here for those interested to download. Things like charts, forms, pictures, videos, etc.

What I am planning on is to list the articles here, then put links to any supplemental information provided below that sub heading.

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.

Something is not right

The Goddamnitnotagain edition:

PA module with burned open output transformer

I went to do maintenance at one of our sites and noticed that a certain transmitter was running at half power. Followed the path of the fault log and found this. When I mentioned it to the station staff, they said, “Yeah, we noticed it sounded a little funny…”

This is the second time this has happened with this particular transmitter. In any case, this is what I get paid for, so I am certainly not complaining. If only every problem where this easy to find.

When I get back out there to replace this, I will bring out my network analyzer and sweep the antenna and transmission line to make sure there are not issues with that. In addition, I will double check all the grounding to make sure the copper thieves have not made off with any critical components like the ground buss bar or #2 solid down lead wires.

A few pictures

Some things I have been working on lately:

A nice row of transmitters
A nice row of transmitters

Finishing up a transmitter site rehab.  The BE FM20T is nearly 20 years old.  The BE FM2C transmitters are new.  There is also a rack of new fiber equipment and CODECs.  This site has good utilization; there are three stations on one tower with a shared STL antenna and generator.

Energy Onix ECO-6
Energy Onix ECO-6

Energy Onix ECO-6 tube type transmitter.  One of Bernie’s better designs, a grounded grid tube with solid state driver section.  This one needed some fans replaced and a new tube.

AM transmitter site.  Looks like these vines have not been cut in a couple of years.
AM transmitter site. Looks like these vines have not been cut in a couple of years.

I wonder how much the guy tensions have changed…

Noticed this after some particularly strong thunderstorms
Noticed this after some particularly strong thunderstorms

The reason why you do not use a POTS line phone during a thunderstorm.

USS Slater radio room
USS Slater radio room

I took a tour of the USS Slater, a museum ship in Albany, NY.  The museum has painstakingly restored the ship to its WWII configuration.  The main transmitter is the RCA TBL-8 seen in the left/center of this picture.  This unit put out 200 to 400 watts CW or 150 watts AM phone.  During the hostilities it was turned off as allied ships observed radio silence unless they were sinking (and sometimes even then).

A little ChiFi tube type RIAA phone preamp.
A little ChiFi tube type RIAA phone preamp.

I have been fooling around with this little 6AK5 preamp.  I find it works very well and sounds better than the built in phone preamp on my Kenwood VR-309.  The FU-29 tube amp did not come with a phone preamp.

This is a short video clip of an audio processor at one of our transmitter sites. The fancy lights around the control knob are designed for the program director. They are saying “Buy me… Buy me…”