WATER! — LOTS OF COOL, CLEAN, WATER!
50 KW KFI ORDERED IT BY THE TRUCKLOAD
By Newcomb Weisenberger

KFI transmitter engineers all shared the transmitter duties. These included the proper operation of the station 24 hours a day. Three shifts of two engineers, plus the chief operator during the day, held the signal of KFI to its assignment 640 KH and very close to 50,000-watts. (Atmospheric interruptions were corrected within seconds.) (Obviously, someone was that close to the panel at all times. They also worked together as they performed maintenance. Maintenance was scheduled from Sunday midnight to daylight Monday morning. A posted schedule detailed each item to be done each week. (Our initials filled in a column listing the items we finished.) Five-week, months added the extra things we did just that often. Each engineer was also assigned one, additional, special responsibility. This was on-going and performed without interfering with the station's operation. To my knowledge, no one at KFI had this assignment but me! I was the KFI Chemical Engineer! I only used two chemicals, and used them very carefully. Both were toxic, violent in nature and carried opposite valence! My tiny lab was set up downstairs in the north east corner. Here was a sink, an overhead shelf, two aspirator jars, lab hose and a waste container. (The waste could not be discharged into the drains.) KFI provided me with a face shield, a full-length lab apron and acid proof gauntlets. It was like High School Chemistry but limited to Hydrochloric Acid (HCl) and Sodium Hydroxid (NaOh). I was limited to this one experiment that I repeated several times a year. KFI used hundreds of gallons of distilled water. The Sparkletts truck would back up at midnight and pay out a large, white, hose into our pump room. We filled the two 400-gallon tanks and the water in the pumps and the circulating system.[1] My assignment was the cooling water for the two water-cooled tubes in the last, 50,000-watt, amplifier.

Carl Sturdy is holding one of the two UV2862 water-cooled tubes. He was one of the first engineers that Mr. (Earle C.) Anthony hired. That long ago, few men had any broadcast experience. Carl Sturdy and Pete Dilts came to KFI as shipboard radio operators. They manned the wireless on iron ore boats on the Great Lakes. Photo courtesy of Marvin Collins

WHY THE TRANSMITTING TUBES WERE HOT

When the FRC, (Federal Radio Com.) Authorized some, fifteen clear channel, stations to broadcast at a power of 50,000-watts, RCA, offered an amplifier module that would boost a 1,000 to 5,000-watt station to 50,000-watts. This would have also required the station to add a 25,000-watt audio modulator.[2] The RCA 50 C avoided that by operating the final, 50,000-watt amplifier in an efficiency mode. It had to be a 75 thousand-watt amplifier during the peaks of audio modulation.[3] It had to dissipate an extra 25,000-watts when it was not modulated!

KFI was putting in, more than three times the power it was broadcasting! Actually, the efficiency was some 33%. Engineers would say that the radio frequency amplifier was operating close to a class B. Meaning that it was an audio amplifier too! This was a commercial choice. It cost less, at that time, to furnish high voltage power than to provide a high power audio amplifier.

The result of this trade-off was that no air-cooled tubes of that size could be made that wouldn't burn out. Water-cooled tubes could carry off the 2/3s of wasted power. These two UV 2862 Amplifiers were immersed in water jackets standing as tall as a small man.

WHY THE WATER HAD TO BE VERY CLEAN.

Electrons hammer into the plate, (anode) of the tube. The metal heats and the temperature rises. The anode is connected to 17,000 Volts DC. The water is connected to ground, (zero volts). Several things must be done to keep this 'short' from happening.

A 22-foot coil of hose or ceramic tubing separates the voltage and connects the water. The leakage to ground is kept to a minimum, if the water is pure! And cool.
(There is a law of physics that the current through the water heats it, and as it is heated more current flows!)

We start with pure, distilled, water. As the water is moved through the pumps and against the hot metal (we use copper pipes and copper or glass lined tanks) the water becomes more conductive. This causes voltage losses and we boost the voltage. This in turn causes more heat.

For many of the early years, KFI regularly, dumped the contaminated, distilled, water and flushed the system with new distilled water before refilling the tanks. (My first meeting with Pete Dilts was seeing his head emerging from a 400-gallon tank.) He had been scrubbing the empty, but still steamy, copper tank with distilled water!

HOW WE KEPT THE WATER PURE

We installed a filtering system that used two resin beds. Each was about eight inches in diameter and two feet tall. They stood side by side and were valved so that they could be connected in series. The water flowed through both when in use. This was a bypass system. Only a trickle of water fed through the filter into the large tank. I made a sight glass from a large test tube. We could check to see the constant flow into the tank. I am still amazed at the impact of that fast-drip on the extensive cooling system.

A dip cell came with the filter. It was cabled to a ph meter that measured the water quality in the system. (I found that it was difficult to collect a small sample and test it without contaminating the sample—A fingerprint could throw the reading off.) I extended the cable so as to dip the cell into the tank. (The 400- gallon sample was error free!) By using one bed to remove (—) ph factor and another bed to remove (+) Ph factor, we had almost, non-conducting water!

The resin beds became contaminated as they filtered the impurities from the cooling system. (My assignment was removing this chemical debris .)

CLEANING THE RESIN BEDS

I filled the each aspirator vessel with one of the two chemicals mentioned above. Made the hose connections. Adjusted the valves and collected the waste. The strong acid and alkaline solutions met with a strong chemical reaction too! The result was a thick, gray, syrupy, soup. This toxic dump was the safest part of the operation!

I was ready and willing to wear my new protective gear! Any spill, hose failure or broken glass would dangerously expose my face and hands to caustic or acid burns. I was as careful of this as with high voltage.

Both beds were flushed with distilled water after the chemical bath. They were now connected so that the system water would pass through them both, one after the other.

The filter could be out of service for several days at a time. (The contamination of the system was a slow process.) The operation of the entire station rested on this flow of cooling water. Safety interlocks prevented any power turn-on unless the water was already flowing!

NOTES

The pump shafts turned inside packing glands. These were adjusted so as not to restrict the shaft or to be so loose so as to leak water. Like all the machinery, the pumps were run alternately a week on and a week off.

Centrifugal pumps have a petcock at the top of the case. This is to open so that the pump will drain properly, when off duty. More importantly, it is used to bleed off air when the pump is put back into service. (An air pocket will prevent its operation. A disaster when it is time to restart the station.) The centrifugal pump can lift water above its mounted level but not from below its mounted level! This limitation is why KFI has two 400-gallon tanks...that is another story.

My exclusive, clean water assignment lasted for about ten years. During that time, transmitting tubes were designed to provide 50kw power while being air-cooled!

[2] Transmitters were built that didn't waste so much power or run so hot. They didn't need me, or anyone else! They could run unattended. The F.C.C. ruled that they could be monitored remotely. KFI bought two of these new transmitters! The first was installed in 1958. The second was added at Buena Park when the old W.E. 5,000-watt transmitter was retired from the Packard building at 10th and Hope St., Los Angeles. KFI's transmitter engineers were then re-assigned to the Vermont studios. There they could switch a failing transmitter for a standby. (A 100%, spare 50,000 watts) by remote control! Man had become more expensive than the machine.

[3] Stations like KFI are amplitude modulated. (AM) Their power is varied from near zero watts to 1/2 again the rated power! This is at the vibration rate of the announcer's vocal cords! This additional power can be added from the modulator, (audio watts) or by using a 75,000-watt transmitter for a 50,000-watt station. When this is done, the station is most efficient when fully modulated. At all other times, this extra power goes into heat. These lost watts heat the tubes, the air, the water and the room.

KFI's transmitting system, (Mike to Tower), can take a word spoken in a quiet studio, and cause it to shake the skies across the Continent!

An interesting design part in the manufacture of part glass and part metal, tubes, is a special glasslike seal between the glass and metal. This amber colored, joint has the temperature coefficients of both glass and metal! (Glass and metal would crack otherwise.)

As the cooling water contacts the hot anode, it separates as steam and collapses against the plate again as it liquefies. (cavitation) This produces a pleasant, singing sound that varies as the modulation changes the dissipation. (Not the program audio but a song of its own.)

During the hot weather months, the cooling water became hot. The tanks, pumps and piping all were hot to the touch. KFI installed a heat exchanger outside the building, just outside the pump room window. This was a huge evaporative cooling tower. It was designed as an air cleaner/washer. Our clean, hot water was circulated through an exchanger cooled by evaporation. The clean, washed heated air was discarded! This was a walk-in unit. We serviced the bearings on the turbine. It was cool inside and the air was free of dust and pollen.

There are jokes about the old days when KFI was steam powered! Not true. But we did produce steam! If KFI was a 'pot-boiler', it was a big one!

"Alone at his desk, on an all night shift, the young KFI transmitter engineer watched the caged monster; on life support, glowing in the dark, singing its wordless song. (Pumps were circulating liquid through its hoses while massive pulses of electrical power probed its insulation.) It was not really alive but it was warm to his touch. He logged its temperature regularly, measured its pulse and listened for its sighs that all was well. At midnight, he started a new station log. It was already tomorrow." Perhaps his relief would be a little early.