FM transmitters – Engineering Radio

A nice pair

I am reminded of a Pink Floyd compilation album from the very early 70s. The music dates back to the late 60s and Syd Barrett. Poor Syd; shine on you crazy diamond!

I recently finished installing these rather nice GatesAir FLX-40 transmitters:

WXBK-FM New York, GatesAir FLX-40 x 2 installation

Audacy New York decided to move 94.7 from the East Orange, NJ location down to the WOR transmitter site in Rutherford, NJ. Acting as contractors for GatesAir, we installed these two transmitters. I can say, I like the liquid-cooled transmitters for several reasons. First, once installed, they seem to be very stable. I believe that the cooling scheme helps prolong the life of the RF devices by keeping the junctions at a constant temperature. Those semi-conductor junctions are tiny for the amount of current that they need to handle. Second, they cost less in the long run to operate. Anytime a refrigerant cycle can be skipped, that reduces or greatly reduces the electrical use. The Heat Exchangers in this system use VFD’s for fan motor control. That means more constant control over the HTF temperature and reduced electrical use on the fan motors themselves.

The pump stations have backup pumps as well. In the newer transmitter firmware, the pump control needs to be set up to automatically failover to the standby unit. It is a couple of clicks in the GUI to do this.

We didn’t have anything to do with the antenna installation, however, it is a good-looking antenna! ERI 4 bay 3 around mounted on one of the WOR towers.

Overall, this was a good project. Lots of moving parts during the installation, but we were flexible working with the client and other contractors and sub-contractors on site.

A little bit of catching up…

I regret not having enough time for writing these days. There are a number of reasons for this. Firstly, much of what I do running my business is mundane and not worth noting. For example; today I am going over work reports and reconciling the bank account. Necessary, but about as exciting as watching the grass grow or reading about drying paint.

However, the rest of the time I have been working on various projects around the northeast, to wit:

In Boston, I took part in converting an LPTV station to ATSC 3.0. That was interesting and I am enjoying the TV work.

Boris Johnson resigns, also one of the first ATSC 3.0 images transmitted OTA in Boston, MA

In Syracuse, we had to lower a TV transmitter from the 23rd floor to the 22nd floor on the outside of the building. The transmitter itself became marooned because an electrical conduit for an alarm system was installed restricting the size of the stairwell.

Carefully lowering a 2KW UHF TV transmitter, State Tower Building, Syracuse, NY

Fortunately, we hired a moving company to do this. I am pretty sure that our insurance does not cover damages from transmitters falling 22 stories.

In NYC, I installed two FLX-40 transmitters for GatesAir.

WXBK FLX-40 transmitters, Rutherford, NJ

“Do you see over yonder, friend Sancho, thirty or forty hulking giants? I intend to do battle with them and slay them.” *“Take care, sir,* those over there are not giants but buildings on the island of Manhattan.”

In Kingston, NY a used BE AM1A (along with a coax switch and dummy load) was installed at WKNY.

Slightly used BE AM1A installed as backup at WKNY, Kingston, NY

7/8 inch coax switch and 2.5 KW oil cooled test load suspended from the ceiling

It is nice that this station has a decent backup transmitter to buttress the aging, yet very reliable Nautel ND-1.

Even though it is a short drive away, I had never visited the 1969 Woodstock Music and Art Fair site in Bethel, NY. It was interesting and being sort of an audiophile, I enjoyed this exhibit in particular:

Your author, standing in front of a “Woodstock Bin.”

From the display:

This speaker stack sat on scaffolding high in the air… festival sound engineer Bill Hanley custom-built eight speaker cabinets for Woodstock, amplifying music and stage announcements across the large festival site… Afterward, the design would be known in the industry as the “Woodstock Bin.”
Bethal Woods Performing Arts center Museum, August 10, 2022

The high-frequency horns used Electrovoice diaphragm S/A compression drivers. I don’t know which driver was used for the bins.

Site of Woodstock ’69 stage, looking up into the field

Looking down from the field to the stage area. Person(s) for scale.

I am also writing articles for Radio Guide, I hope that you are enjoying them!

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.

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.