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Collins 21E |
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Driver Cabinet, Power Cabinet and Power Amplifier Cabinet |
| From left to right, Audio and RF Driver Cabinet, Power Supply Cabinet, and RF Power Amplifier
and Modulator Cabinet. Power Supply Cabinet: Mercury vapor rectifier tubes (replaced with plug-in solid state diode modules) All units have their relay controls inside the bottom panel. |
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| From Manual: Controls description diagram. |
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Driver Cabinet |
Final Amplifier and Modulator cabinet |
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On RF Power output cabinet: PA Loading, Plate Tuning Grid Tuning |
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Tube Compliment For the 21E |
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Quantity |
Type |
Purpose |
| 1 | 6AU6 | Crystal Oscillator |
| 1 | 6SJ7 | Buffer or Multiplier |
| 1 | 807 | Amplifier |
| 2 | 4-125A | Driver |
| 1 | 3X2500A3 | Final Amplifier |
| 2 | 6SJ7 | Audio Amplifier |
| 2 | 4-125A | Driver Amplifier |
| 2 | 3X3000A1 | Modulator |
| 1 | 5U4G | Exciter Bias |
| 2 | 866A (Replaced with Solid State Diodes) | Final Amplifier Bias |
| 2 | 866A (Replaced with Solid State Diodes) | Low Voltage Plate Supply |
| 2 | 872A (Replaced with Solid State Diodes) | Intermediate Plate Supply |
| 6 | 575A | High Voltage Plate Supply |
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| From Manual: Bottom of cabinet on the left shows cooling blower for modulator and final tubes. Top shows enclosure shield for output network. Top of cabinet on right shows enclosure shield for audio output network. |
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View of transmitter building and antennas. |
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Driver RF Chassis on left. Audio Chassis on right. |
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Cooling fan for power supply cabinet. |
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RF Amplifier choke, fixed capacitor and variable vacuum capacitor. |
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| Chain couplings for controls. I don't know which. |
Solid state diode modules, that replace the mercury vapor tubes. (No exciting flickering to watch!) |
5KW Harris SX-5
transmitter, that replaces the 21E. I was told at this writing that it will become the Aux and be replaced by a Nautel XR3. |
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| Two views of 3X3000A1 Modulator tubes. | 3X2500A3 One of two, Final tubes behind tuning and loading controls. |
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