Radio Station KPO
50 KW G.E. Transmitter
Belmont, California


KPO’s 50 KW transmitter, model RT-152-G, was custom-built by General Electric on contract to N.B.C. The contract also included the construction of the transmitter building, cooling pond and antenna system.

The driver section of the transmitter was located to the left of the operator. It consisted of three cabinets. The left cabinet was the power and control unit for the driver section. It included the mercury vapor rectifiers for the 600 VDC and 3 KVDC circuits. The center cabinet contained duplicate plug-in crystal control oscillators, two intermediate RF power amplifiers (UX-860 and UV-849), the speech amplifier (2 UV-211) and the modulator (2 UV-849). Modulation took place in the UV-849 intermediate amplifier section. The right cabinet is the 5 KW linear power amplifier, with two water-cooled UV-863 tubes.

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The 50 KW linear power amplifier was located on the left-hand side of the center section, as viewed by the operator. It utilized two UV-862 water-cooled tubes. To the immediate right of the power amplifier was a monitor speaker and the main 50 KW rectifier section, which utilized six UV-857 mercury vapor rectifier tubes. There was also a seventh tube which operated as a hot standby, capable of replacing any of the other tubes at a moment’s notice.

The panels to the right of the operator were the main control panel for the motor generators and water pump motors, as well as chart recording voltmeters and ammeters.

Voices Out Of The Fog

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All articles copyright © 1997-2006 by John F. Schneider. All rights reserved.
Reprinted with the generous permission of the author.

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