Let’s Toss Another Expensive and Useless Rule!

The seemingly obsolete NRSC mask measurement for AMs is a waste of time and resources
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Larry Langford

Larry Langford is owner of WGTO(AM) and W244ds in Cassopolis, Mich. He has been in radio since 1965. His commentaries on radio issues such as those facing AM owners are a recurring feature. Read his past articles by searching for “Langford.”

OK going back into the memory archives ... When I got in this business in the early ’60s (the days before unattended operation) we had to fill out a transmitter reading log every 30 minutes.

The FCC required you to write down parameters of the transmitter oscillator and final power amplifier (PA) such as plate current, plate voltage, computed power output in watts, RF line current and frequency tolerance. You had to trim the values if they were out of limits. If you had a directional you had to take phase and ratio readings as well for each tower and common point RF current. It took a few minutes especially if you were on remote control and had to listen to the chunk-chunk as the two-wire remote system counted through the steps as the system responded to the phone dial that you had to use to read different stages.

[Read: AM: Some Engineers Just Don’t Know How to Do It]

If you were a combo DJ on a live board it was tight to get it done during one record. Wow! One thing I found out early, the chief engineer was very serious about you filling out those reading logs. But as you can imagine on at least a few occasions there was a little “faking” going on ...

In later years the FCC backed off and we could take readings less often. I think it was then every three hours. Then the commission tossed the daily requirement all together. The idea was that transmitter systems and DA systems had become very stable and the readings were just not necessary as long as the chief kept an eye on things as often as necessary to ensure compliance.

At one time stations were required to keep a modulation monitor and a frequency meter in full-time operation. Back then it was possible for an AM transmitter to drift near the edge of the ±20 Hz limit, especially if the crystal oven was faulty, but now transmitters are rock-solid and easily maintain frequency within a cycle or two. So while the chief is still responsible for keeping things within legal limits no longer do we need full time equipment to make sure. So it is in that spirit that I question FCC 73.44, the requirement that AM stations do NRSC mask measurements.

The masks were required after the NRSC 10 kHz limit was adopted. And many stations complied with some form of outboard adapter on the processor. The rule is now decades old and compliance is a breeze because every processor built for use in the U.S. has the mask built in and all greatly exceed the required limits of the FCC. So why are we still mandated to do the annual readings?

Sure it’s a good way to meet your friendly consultant face to face now and then but are the measurements really necessary? Unless the station has museum-like equipment in operation like a Gates BC1T driven by a Volumax, it should be assumed that occupied spectrum limits are good!

If we don’t have to certify on frequency operation daily why must we bear the expense of a compliance measurement every year for occupied spectrum? A long time ago we got rid of twice hourly station identification at the top and bottom of each hour, having an engineer at the transmitter site full time, having operators post a Third Class Radio Telephone permit, annual “proof of performance” audio chain measurements and much more while recently we have eliminated the Main Studio, Rule, and on-site Public Files. I think is just natural that we should dump the required spectrum annuals as well!

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