May 2012 – Page 2 – Engineering Radio

WVTQ Mount Equinox, Vermont

The transmitter for Vermont Public Radio, WVTQ 95.1Sudbury is located on Mount Equinox, near Manchester Vermont. Mount Equinox is one of the better mountain top transmitter sites to get to as it has a good access road, no jeep trails through the woods or ski lifts, etc. The Summit is 3,580 feet (1,175 m), which is the third-highest peak in the green mountains. On a nice day, the view from the top is spectacular:

The southern view with US Route 7 cutting through the valley below.

WVTQ is a part of VPR’s classical music network. They had a Nautel VS-1000 that had developed issues with the directional coupler. This unit was repaired and re-installed:

WVTQ Nautel VS-1000 transmitter, Mount Equinox, Vermont

The transmitter has a 7/8 EIA flange on the back, which had an elbow, then an adapter to a type N connector all unsupported. My boss felt that perhaps that perhaps too much weight on the EIA flange caused the crack in the directional coupler.

WVTQ transmitter racks and STL equipment

The transmitter site used to be in the basement of the hotel, but as that building no longer exists, it was moved over to the former RADAR site. The RADAR site consists of four 80-foot towers arranged in a square around a building. These towers now support two-way radio equipment and the like

WVTQ transmitter site, Mount Equinox, Vermont

Your author (left) with Rich Parker of VPR discussing the finer points of GPS antennas.

Ladder to the top of one of the towers.

Hang Glider's view, east side pulloff, Mount Equinox, Vermont — Hang Glider’s view, east side pulloff, Mount Equinox, Vermont

View from the turn-off on the east side of Skyline Drive. Known as “hang glider’s view” with good reason. This is on the saddle that connects little Equinox with big Equinox.

On a nice day, such as yesterday, it is very pleasant. When the road is covered in ice and snow, not so much.

EAS text to speech permitted, not required

The FCC reverses its former position on EAS text-to-speech, permitting stations to begin using it today (May 7, 2012). The FCC’s main issue with Text To Speech (TTS) was that it may not render the text accurate enough to be understood, especially in emergencies. This can lead to confusing messages and defeat the purpose of EAS altogether.

I have played around with some text-to-speech software and indeed it can mangle words, mispronounce punctuation as a part of the sentence structure, mumble, etc. Further, as I have said before, listening to some robo voice is very impersonal. But, I suppose that is the point, isn’t it; some big government agency computers generate messages that no one person is really responsible for. Bureaucratic paradise.

Summing to Mono

It is surprising to me how many times I have seen this done incorrectly in the field. Summing a stereo source, whether it is balanced or unbalanced is not simply twisting a couple of wires together. This will effectively reduce the impedance of the outputs by one-half. With newer, active balanced outputs, this may cause damage to the output amplifiers.

The parallel resistance formula is thus:

Therefore a 600-ohm stereo output tied together would look like this:

Rt = 1/(1/600+1/600) or 300 ohms.

It also creates an impedance mismatch with the next piece of gear, which will affect the common mode noise rejection of the circuit.

The best way to sum is through a resistive network. That way stereo separation is maintained, the impedance of the output circuits is maintained and the output amplifier will not current cycle. That looks like this:

Pretty easy to fabricate in the field. It is good to do things the right way, it sounds better on the air too.

Harris exits the broadcast industry

When they sold their Broadcast Equipment supply division to SCMS a few years ago, the handwriting was on the wall. Even so, it is a little surprising that they would exit broadcasting altogether.

The decision to divest in no way reflects the quality of the work Broadcast Communications performed in support of our customers and our company. Harris simply determined that Broadcast Communications could provide higher value and operate more effectively under a different ownership model.

They are spinning the broadcast division off to a new owner rather than completely shutting down the operation. In an e-mail received from Harris Morris, President of, Broadcast Communications Division, clients and customers will still receive support for existing products:

In the interim, Broadcast Communications will continue to be a part of Harris Corporation and operate business as usual. Our valued relationships, both longstanding and new, remain our top priority. The global Broadcast Communications team will continue to work diligently to ensure our commitment to our customers and partners remains steadfast, our execution to fulfill commitments is flawless, and our progress against strategic objectives remains focused.

Well, there you have it. This affects such things as Harris transmitters (AM, FM, TV, HF) and support, Harris consoles and studio furniture (previously Pacific Recorders and Engineering or Pacific Research and Engineering, AKA PR&E), and Intraplex STL systems, among others.

What does all this say about the future of terrestrial broadcasting?

We live in interesting times.