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PowerClamp Is Worth the Price

User Report: Thanks to my ‘magic box,’ it’s been 14 months since I replaced a MOSFET

ODESSA, Texas — In the first three years of ownership of KCKM(AM) 1330 in Monahans, Texas, I spent a great deal of time changing MOSFETs in my 5 kW solid-state transmitter. I went through an average of 50 per year, something I had never experienced before.

I asked Mike Vanhooser from Nova Electronics in Dallas to take a look at the situation. Mike quickly zoomed in on the source: “dirty power.”

Our AM transmitter is in the middle of an active oil field eight miles from town. We are surrounded by pump jacks cycling on and off around the clock.

Recently, KCKM received a CP to increase our day power, and I wanted to protect the new transmitter. I had heard positive comments about the PowerClamp TVSS from several southern California engineers. Mike and I discussed our options and decided to go with the PowerClamp TVSS, which is made by Sine Control Technology.

Our PowerClamp TVSS arrived about two weeks after I placed the order. Mounting and installation took less than 30 minutes and that was it. We wired it to a breaker on the electrical panel and just turned it on.

Did the PowerClamp solve our problem? You bet. I sometimes refer to our PowerClamp unit as the “magic box” because it’s been 14 months since I replaced a MOSFET.

The price of the PowerClamp TVSS wasn’t an issue with me, I just wanted to resolve the problem. Every large-market radio station should have one, period.

But I have been in broadcasting long enough to know there are some small- or medium-market managers who will look at the price of the PowerClamp TVSS and find it to be a bit costly. According to Sine Control, a typical single-phase installation would cost approximately $2,600, with three-phase configuration approximately $3,200.

I understand that every purchase must be justified. But I am talking about reliability.

If your station transmitter suffers from some unique, recurring problem that is affecting your ability to stay on the air or maintain licensed ERP, the unit may pay for itself by saving on engineering fees and component costs.

(Sine Control emphasizes that the size of the PowerClamp does not depend upon the size or power of the transmitter; it’s based on the lightning risk of the area. For most areas in the U.S., the company suggests a Series 8 PowerClamp, rated at 150,000 surge-amps of suppression. For very high lightning areas — e.g., the Southeast — it suggests a Series 10 unit, rated at 200,000 surge amps.)

We just built a new Class A FM from the ground up. The transmitter site has a PowerClamp TVSS on the wall, next to the main breaker box. Soon, there will be a PowerClamp at a location often neglected but still worthy of the protection offered by the PowerClamp TVSS: our studio.

Bob Souza is managing partner and chief engineer for KCKM(AM) and KTXO(FM).

For information contact Hank Landsberg at Sine Control/Henry Engineering in California at (626) 355-3656 or visit