General Electric Co., Schenectady, N. Y. 
General Electric was one of the pioneering companies in broadcast. What was left of the broadcast line was sold to Harris in the 1960s. (The small appliances division was sold to Black and Decker.)
Transmitters:
AM transmitters:
(Some lists use a "4" as a prefix.
The "4" refers to the GE Broadcast Division)
Click picture to enlarge  Remarks 
4BT20A  250 W Courtesy: Steve WB3HUZ 

XT1A  1 kW  1947
WKIP  Serial #11 

4BT21A  1 kW  
4BT22A  5 kW  
4BT23A  10 kW  
4BT25  50 kW  
4BT25A  50 kW (1947?)  

4BT50A  50 kW 
4BT50A1 50 kW KCBS 

4BT50B  
4BT50C WSM 

BTC50C 50 kW This is a Canadian version Originally at CKNW, Westminster B.C. ... rand Turk Island 
FM transmitters:
Model  
BT11B1 10 W  
BF1A  250 W  
BF1B  250 W  
250 W High School Station WBXL  Baldwinsville, NY 

BF2A  1 kW  
BF2B  1 kW  
BF3A  3 kW  
BF3B  3 kW  
BF3F  3 kW  
BF3F  3 kW  
BF10A  10 kW  
BF50A  50 kW  