[BC] RCA BTA5L & and other numbers (MAKE CORRECTIONS TO LIST) HISTORY

[DHultsman5 at aol.com]

In a message dated 4/30/2008 5:16:47 AM Central Daylight Time,  
miltron at mindspring.com writes:

You're  correct; what was I thinking ? I looked in my red hardback catologue; 
the  BTA-5F used 892Rs. The BTA-5L must have been the next model that used  
5762s
M
----- Original Message ----- 



***************
 
Even though the letter sequence was different I believe the 5L was the  
Ampliphase???
 
BTA-5D  1 kW Driver Cabinet into 5 kW PA 891 Class B Modulators into  892 RF 
Amp
BTA-5E   Same Design Different  cabinet
BTA-5F   new Design Mainly Cabinet 892's Modulating single  892
BTA-5G
BTA-5H
 
               One of the above was the first use two each  5762 RF 
amplifiers   Modulated by two (5762's or) 3CX3000 and used tube type thyratrons for 
power  control.  Three Brown cabinets. 10 kW. version used three 5762's in the  
PA.
 
In this era the numering changed as I recall.
 
BTA-5R  two Cabinet  two 3CX-3000 modulating a single RCA  5762 with Cathode 
and plate resonators
BTA-5T  three Cabinet 5 kW same tubes could be upgraded to 10  kW  (Same 
Cabinet as 10 kW)
The later model of the tha above same two transmitters had a different  
letter and used the RCA Version of the rectangular API style meters.
 
There were several color changes in these models,  Red,  Dark  blue with lite 
blue doors and dark blue cabinets & doors.  
 
The 5762 tube was stretched as its nominal current rating was 1 Amp.   It 
took between 1.25-1.30 Amps to make 5 kW. with 5400 Watts into a DA  system.  The 
type, using both cathode and plate harmonic resonators  could barely make 
this power and have an positive peaks.  RCA sold  alot of them but lost out 
mainly to positive peak modulation performance.
 
The Next transmitter to follow the 5R/5T series was the Ampliphase  
transmitter.  As I recall RCA didn't make a 5 or 10 kW. Ampliphase using  the older 22 
tybes exciter as the did with the 50 kW.  The first five and  10 kW. were made 
using the RCA solid state Ampliphase Exciter and was in a blue  cabinet about 
60 inches wide.
 
I recall,  the first 5 & 10 kW. RCA Ampliphase rigs using the  solid state 
exciter were the BTA-5L and BTA-10L.  
 
I know we have some more knowledgable RCA experts on this forum.   Please add 
to and update this list.
 
Dave Hultsman
Continental Electronics



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