[BC] MORE WESTINGHOUSE 50 HG

[DHultsman5 at aol.com]

In a message dated 1/8/2008 6:35:39 PM Central Standard Time, 
stanleybadams at yahoo.com writes:

> WAS IT DRIVEN BY 5 KW UNIT LIKE GE, RCA AND WESTERN ELECTRIC?  ALSO LOOKING
> FOR MORE INFO ON STATIONS THAT HAD THIS RADIO..

The Western Electric transmitters were mostley modulated in a low level RF 
stage by modulating the grid of and RF driver tube.  After that stage the 
amplifier following were normally linear or of Doherity design.

Early RCA transmitter were not plate modulated and used linears to achieve 
their high power at low efficiencies.   I am not certain which RCA was the first 
50 kW. Plate modulated rig the 50E or the 50F.

In the case of all Western Electric transmitter until the last of their line 
and the first of the Continental line, the modulation was done by varying the 
bias on the peak tube and the carrier tube..   If you had a 5 kW. rig that rig 
had a 5 kW. Doherity amplifier,  ie: the WE 405A/B series transmitter was the 
driver for the WE 407, 50 kW.  There were two Doherity amplifier one at 5 kw. 
driving another for 50 kW.

In the case of early RCA transmitters a 5 kW. transmitter would use the 
modyulator as an audio driver to the 50 kW. Class B modulator tubes.  The 5 kW. RF 
stage typically an 891 or 892 drove the parallel tube Class C RF stage 
modulated by the above. In this way the lower power transmitter was used in the 
higher power transmitter.

In the case of the Collins 20V series 1 kW. transmitter the 4-400's in the 
modulators were changed  to drive the Modulator grids of the Class B modulator 
in the 21E & 21M, 5 and 10 kW. transmitters.  The first cabinet was the RF and 
audio driver for the 5/10 kW. modulator and PA stages.

Nearly all RCA's from the late '40's till the low power 5L and 10L  Lower 
power Amplifiers used the RCA 1 kW. cabinet as an RF driver and a modulator 
driver in their higher power 5 and 10 kW. rigs.

Dave 


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