This is the Hot Glass Archive Section of
The Broadcast Archive
Maintained by:
Barry Mishkind - The Eclectic Engineer
Last Update 11/2/08
To a veteran broadcast engineer, there is nothing quite like the glow of the glass tubes in a transmitter. The Modulator and Power Amplifier tubes are among many things missing in solid-state transmitters, however, even they had morphed into ceramic tubes at higher powers.
Still, the pulsing glow of the Modulators and the warm bright PA's of a well operating transmitter ... well, it really doesn't get any better.
Here is a sampling of the Hot Glass from the Tube Era of broadcasting:
|
1 kW and Under |
| Tube | Some of the transmitters that used these tubes. | |
| 3-500Z | Collins 828D-1, Continental 314R-1 | |
| 4-250A | Collins 550A-1 | |
|
|
4-400A | Collins 20V series |
| 4-500A | McMartin BK-1000 | |
| 4CX3000A | Gates Vanguard | |
| 5-500A | Collins 820D-1 and 820D-2 | |
|
|
450TH | |
|
|
833A | Gates BC-1T, BC-1G |
|
5 kW |
| Tube | Some of the transmitters that used these tubes. | |
| 3CX2500 | ||
| 3CX3000 | ||
| 3CX5000 | ||
| 4-1000A | McMartin BK-2500, BK-5000 | |
| 4CX5000A | ||
| 4CX10000A | ||
| 5762 | ||
| 891R | ||
|
|
892R | Most non-Western Electric transmitters. This RCA tube had very brittle filaments, according to Bob Groome |
| DX-516 | Longer life than the 892s? |
|
10 kW |
| Tube | Some of the transmitters that used these tubes. | |
| 3CX10000 | ||
| 4CX5000A | ||
| 4CX15000 | ||
| 5762 | ||
| 891R | ||
|
|
892R | Most non-Western Electric transmitters. This RCA tube had very brittle filaments, according to Bob Groome. |
|
50 kW |
| Tube | Some of the transmitters that used these tubes. | |
| 4CX3500A | ||
| 5671 | 1947 - RCA made this to replace the 9C22. | |
| 6696 | ||
| 6697 | ||
| 893R | RCA Tube | |
|
|
893AR | KEX, Portland used this one |
| 898 | RCA 50C 50D (this is essentially an 862 with filaments modified for three phase heating). | |
| 9C22 | Used in the original BTA-50F, replaced in | |
|
|
WL5891 | Westinghouse 50HG-1, GE BT-25, Gates BC-50B and BC-50C |
| UV207 |
GE (WGY)
Stan Adams says: "Parasitics would often cause overheating and would blow the grid low value resistors and the plate caps. It did not like operating at certain voltages." |
|
| UV 862 |
RCA 50B, 50C (RCA's version of the GL-862A) water cooled |
|
| UV 863 | ||
| GL-862A |
early GE transmitters water cooled. |
|
Really "Big Glass" |
| Tube | Some of the transmitters that used these tubes. | |
| GL-862A | WLW's 500 kW | |