The original site of KFI ... 
at the Packard dealer
1000 S. Hope St, Los Angeles

In 1931, KFI installed a 50,000 watt transmitter in Buena Park
 (Southeast of LA) in the new transmitter building.

The Buena Park facility
The transmitter is upstairs, downstairs were the power transformers, generators, etc.

Over the door, the KFI call is shown in tiles. On the door frame, you can
notice how the tiles depict the antenna and radio waves emanating from the site.

Installed in 1931, it served as the main until a Continental 317B was installed in 1959.

"Both transmitters carry control and supply voltages. Unless the 250V DC is more damaging to the body than about that much AC those would seem to be equally dangerous. However, the old tube transmitter has, in addition, a secondary hazard in its plate supply, circuitry , switching, metering , sockets and contactors.

"The 17,000-VDC plate supply, alone, employed a HV vault twice the size of the Harris transmitter with air insulated conductors, exposed bolt-on connections and an open filter bank of ganged capacitors. The HV full wave three phase MV rectifier assembly was as dangerous as the transmitter it fed.

"I think that operating under such high tension, insulators, transformers, capacitors, coils etc are more apt to fail. That there also would be more sustained arc overs than if operating on a few hundred volts.

"The final metering would not need to be double insulated as in the 50B. I think one would be more apt to survive an accidental contact with 250V than a brush with 17 kV. Given the resistance of the body in this instance.

Less maintenance is required, for the Harris, the installation is safer. There is less exposure to danger. The point being that the more times you visit a dangerous place, the more ones safety is challenged.

The use of 100% standby transmitters is a move to safety. Having removed the added danger of a hurried repair with off air time a factor.

"The 50B was interlocked with the final filament voltage. The low voltage interlocks proved to be fail safe; i.e. all contacts had to be really clean and secure to close the circuit. A "Danger Man Working" sign was hung on the main switch while in the open position. There was a near accident: the vault was not interlocked but was secured by a heavy chain and padlock. It took deliberate action to go inside. A vacation relief man, being trained, closed this switch while the engineer was entering the vault on the first floor. When the vault door was opened, he could hear the H.V. corona discharging over the filter bank!

"We made it a practice, whether or not it was necessary, to inform each other where we were at all times, day or night. This is a very important safety measure. When a man was sent to the tuning house, he reported by telephone. Again the house was locked and within a closed fence and locked gate. Carrier power was not applied without making telephone contact first, as once within the fence, there was no protection from the tower.

"When off the air for maintenance we made it a practice to ground the tower with a shorting switch before cleaning the base insulator. Brush discharge often caused powerful arcs across the protective horn gaps.

"The old transmitters also used open framed rotating motors, generators and water pumps. This too is a safety issue, mechanical and electrical. The bias machines were 1,000 volts. ( we checked the bearings every two hours, cleaned the contacts and pushed down the brushes as they wore away.) We used commutating cleaning sticks on the exciters for the huge 50/60 cycle changer.

"The safety practices were those used with all moving machinery. No loose hair or clothing, secure footing, good lighting, safety glasses and attention to the task. By and large these safety practices were in force, but not forced. Not part of the transmitter safety but part of the engineers' safety, our machine shop with its power grinders, milling and drilling machines , compressor and lathe required good safety practices too.

"To my knowledge, no KFI Engineer has had a serious work related accident."

This picture was taken after Anthony purchased KEHE and renamed it KECA (it is now KABC).

750 feet tall, with the additional pressure from the guy wires, the tower may exert approximately 800 tons of pressure on the relatively small location where the tower sits on the insulator.

Electrically the tower is 175 degrees (just under a half wavelength) tall. 

Note: Base insulators are only 4 inches thick. They are stronger because of the curve and being hollow!

The auxiliary antenna is about 46 degrees tall, a guess would put radiation at about 220 mV/m/kW at 1 km, which is only 36 percent as efficient as the minimum. 

All that means with 50 kW into its old stick, KFI was getting about 53.3 kW out, effectively. And with 25 kW into its auxiliary stick, KFI is getting about 9.2 kW out, effectively.

This picture was taken in 1994, after construction had started to "hem in" the tower.

You can see how the local business district is built up right around the tower. 

....

This permitted the long running, RCA 50B (modified into a 50C) to be finally retired.

Harris DX-50, installed in 1992.

===>
Remnants of the old guy wires in the dumpster.

Pictures of the disaster are located here.

The  "Towers Down!" War Story section.

More KFI History

Newcomb Weisenberger's KFI Stories

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