[BC] Transmitter metering

[RichardBJohnson at comcast.net]

During the evolution (devolution?) of radio, many standards were changed as technology developed. In the beginning, radio stations operated much like power stations. There needed to be a licensed engineer on duty any time the transmitter was in operation. His duties included, but were not limited to:

(1)     Recording the final amplifier plate current and plate voltage
(2)     Recording the antenna or common-point current
(3)     Recording the frequency deviation using an approved instrument
(4)     Recording the crystal oven temperature
(5)     In a directional array, recording the magnitude and phase of the appropriate radiating elements.

These readings were recorded at 30-minute intervals. Furthermore, the operator on duty needed to make certain that "modulation in excess of 100% of frequent occurrence" did not occur, plus the modulation levels needed to me maintained "as high as possible consistent with..."

Because a licensed engineer (--yes called an engineer in those days) was required to be on duty, the FCC even required that there be toilet facilities at the transmitter sites.

Eventually the FCC authorized remote control. There still needed to be an "operator" (name change, representing a Third Class Licensee) on duty that would log the transmitter parameters at 30-minute intervals and make antenna or common-point meter readings daily within 30 minutes of a pattern change. In the case of a directional array, this operator needed to have a First Class Radiotelephone license when the array was in operation, typically nighttime.

Compare this with the fully automated stations of today. When I started designing broadcast equipment, it was my many applications through the FCC standards division which removed the requirements for crystal-oven heaters, thermometers or indicators like flashing lamps, "plate" voltage and current for solid-state transmitters, dial (scale) length for digital meters, etc. Some manufacturers simply ignored the rules and got away with it. The companies for which I worked changed the rules where appropriate.

I thought broadcasting was rule-based. This would level the playing field and assure that the owners of the spectrum (you and me) would be afforded its best possible use. We changed the rules that were not appropriate as technology made them redundant or obsolete.

Even before I was actually designing equipment, I had a first-hand look at the FCC rule making. I worked for WCRB, the Boston area (Waltham) concert music station run by Richard L. Kaye, a dynamic-range advocate. WCRB was often cited for not maintaining the modulation levels specified in the rules. When he would receive the citation, he would spend a lot of money for lawyers defending his position of maintaining the dynamic range of a concert hall.

Radio station WCRB was the most technically perfect station for which I ever worked. We even created the NAB recording standard from the unobtainable RIAA standard. I asked Nathan Hallenstein, the engineer in charge of the FCC radio district, what could be done about this problem. He said; "Change the rules. I report only rule violations, not my preferences..."

Richard L. Kaye, petitioned the FCC for a waiver of the rules. I petitioned the FCC standards bureau for a revision to the rules, noting that stations would certainly keep the modulation levels high of their own accord. We both got our requests satisfied although everyone wins when it is a rule-change.

The same evolution has occurred with power stations. Nowadays, only nuclear power stations are manned. Once every so often, some "consultant" goes around to the power stations, located up and down the rivers, and checks to see if they are still there. Maybe once a month, someone shows up at the coal and old-burners to check that the supplies were delivered and the fly ash carted away. It still seems a lot like broadcasting!

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/

----- Original Message -----
From: "Mark Humphrey" <mark3xy at gmail.com>

The former 2-1/2 page rule that required meter set back was 73.40,
"Transmitter; design, construction, and safety of life requirements":