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PowerClamp Takes Mystery Out of Failures

User Report: Henry Engineering helps engineer solidify transmitter performance

PowerClamps have repeatedly demonstrated their ability to eliminate power line surges and glitches that cause tripped breakers and serious damage to transmitter plant equipment.
LOS ANGELES My experience with Henry Engineering’s PowerClamp Transient Voltage Surge Suppressor units began in 1988, although at that time they were known by the name Sine Control TVSS.

I am the contract transmitter engineer for KWVE, a 25,000 watt FM station in San Clemente, Calif. For several months, the station was experiencing a problem with the transmitter, which was located on a mountaintop that’s two-hour drive from the station’s studios.

The problem was simple but annoying: Almost every Thursday morning at about 8 a.m., the transmitter would throw its main breaker and the station would go off the air. This would require someone to drive up to the site, reset the breaker and get the transmitter back on the air.

Every time this happened, we’d try to locate evidence of whatever caused the breaker to trip, but nothing was ever found. The local utility company was contacted, under the assumption that the problem was power line-related. They ultimately issued a 23-page report, explaining that it wasn’t due to anything the utility company was or wasn’t doing.

About that time I was contacted by a representative of Sine Control International. They claimed to have the solution to the problem in the form of a highly effective surge suppression device.

We had tried other “surge suppressors” with no improvement in the situation. Since we were at our wit’s end, I agreed to try one of their units. It was installed. The problem went away and never returned. Ever since, I’ve been a big fan of these units, which are now marketed by Henry Engineering as the PowerClamp.

Smooth sailing

A few years later, I became chief engineer of KPWR, one of Los Angeles’s major FM stations. They were using a pair of older CCA transmitters. They too had the occasional problem with one (or both) transmitters tripping the main breakers. And again, someone (usually myself) had to drive up the mountain to reset the breaker. Since “I had seen this movie before,” I installed a PowerClamp Series 8 surge suppression unit. Again, the problem went away and never returned.

In 1992 we upgraded to a new transmitter plant on Mt. Wilson, the 6,000-foot mountaintop that serves Los Angeles with most of its FM and TV signals. I installed a pair of Continental 816R3B transmitters at this site, which also housed another FM transmitter and a TV transmitter. Taking a clue from my past experiences with mountaintop power, I installed a PowerClamp Series 8 surge suppressor on the transmitter’s AC power input.

It paid off. A few months later, there was a significant power line surge. The surge (or whatever it was) caused my transmitter to “hiccup,” but come back on the air after a few seconds. There was no damage. The other FM and TV transmitters in the same building sustained serious damage. They were off the air for several days until repairs could be made. The cost of their repairs greatly exceeded what I spent on the PowerClamp TVSS unit.

I currently am the engineer manager for the Los Angeles cluster of several broadcast facilities under common ownership. Being responsible for 13 radio stations means my time is limited, and there is no room for “taking chances.” For this reason, I have installed PowerClamp units on virtually every transmitter for which I’m responsible. At one transmitter plant, we previously had experienced unexplainable off-air episodes about once every four to six weeks. Since the PowerClamp unit was installed, we haven’t had such an occurrence in over a year.

I’ve also noticed an increase in tube life. Our Harris transmitter used to consume final tubes at a rate of about one per year. After installing a PowerClamp unit, tube life has increased. We’re now 16 months into a tube and it’s still going strong. I can only conclude that keeping voltage spikes out of the tube is having this positive effect.

I’m convinced that PowerClamp TVSS units are well worth their cost. In my 20+ years of first-hand experience, they have repeatedly demonstrated their ability to eliminate power line surges and glitches that cause tripped breakers and serious damage to transmitter plant equipment. And apparently they maintain their effectiveness, since the unit that I installed at KWVE in 1988 is still working well.

For information, contact Henry Engineering in California at (626) 355-3656 or

The author of this article wrote under a pseudonym to comply with his employer’s policies about endorsements.