Note
QST, May 1963, p. 137.
QST, Jan 1964, p. 129.
Allied Radio catalog 1965 (copyright 1964), p. 322.
Drake's first transceiver used three 12BJ6 sweep tubes in its final amplifier to generate 300 watts PEP input. The TR-3 offered full coverage of 80-10 meters and featured linear PTO tuning. Although primarily designed for sideband operation, it could also be used on CW and controlled-carrier AM. A pair of 2.1 kHz crystal filters provided upper and lower sideband on transmit and receive. External power supplies were required for both mobile and fixed operation.
Frequency Ranges: Covers seven 600 kHz band segments:
3.5 to 4.1 MHz
7.0 to 7.6 MHz
13.9 to 14.5 MHz
21.0 to 21.6 MHz
28.0 to 28.6 MHz
28.5 to 29.1 MHz
29.1 to 29.7 MHz
Operating Modes: Supports Upper Sideband (USB), Lower Sideband (LSB), Continuous Wave (CW), and Amplitude Modulation (AM).
Power Output Ratings: Rated at 300 Watts PEP input on SSB, and 260 Watts input on CW and AM.
Sideband Selection: Employs two specialized 9.0 MHz crystal lattice filters (2.1 kHz bandwidth at 6 dB down). Switching sidebands selects between upper or lower filters without requiring oscillator frequency shifts. Unwanted sideband suppression is greater than 40 dB, and carrier suppression exceeds 50 dB.
AM Operation: Incorporates a controlled-carrier screen modulator for transmission (compatible with SSB linears) and product detector reception using the exalted carrier method to reduce selective fading.
Voice Control & Keying: Features built-in VOX and Push-to-Talk (PTT) capabilities for voice modes. CW features grid-block keying free from chirps or clicks, using a shifted carrier approximately 1 kHz off the receive frequency.
VFO & Premixer Circuitry: Utilizes a high-stability, linear permeability-tuned VFO that tunes 4.9 to 5.5 MHz across all ranges. On 80 and 20 meters, the VFO combines directly with the 9.0 MHz IF. On 40, 15, and 10 meters, the VFO heterodynes with an overtone crystal oscillator inside a premixer stage.
Dial Calibration: Features 10 kHz main dial divisions with an adjustable skirt knob providing interpolation down to 1 kHz. Effective circular scale length exceeds 14 inches. Frequency drift is less than 100 Hz after warmup.
Specifications
– Dial Calibration: Main dial marked in 10 kHz increments; movable skirt knob provides interpolation down to 1 kHz. Circular scale equivalent length is greater than 14 inches.
– Frequency Stability: Less than 100 Hz drift after warm-up.
– DC Power Input:
SSB: 300 Watts P.E.P. input
CW / AM: 260 Watts input
– Carrier Suppression: Greater than 50 dB.
– Unwanted Sideband Suppression: Greater than 40 dB.
– Carrier Frequency Shift: CW keying shifts the carrier frequency approximately 1 kHz off the receive frequency.
– Keying Method: Grid-block keying on CW.
– Microphone Input: High impedance (3-pin connector).
– Sensitivity: Less than 0.5 uV for a 10 dB Signal-to-Noise ratio.
– Selectivity: 6 dB Down: 2.1 kHz bandwidth (using dual 9.0 MHz crystal filters), 60 dB Down: 7.5 kHz bandwidth
– Intermediate Frequency (IF): 9.0 MHz
– Audio Output Power: 2 Watts into a 4-Ohm load
– Calibration Standard: Internal 100 kHz crystal calibrator.
– Antenna Impedance: 50 Ohms nominal (SO-239 connector)
Tube Lineup (20 total)
(3) 12JB6 (or 12JB6A) Final power amplifier stage.
(5) 12BA6 IF amp, receiver RF amplifier, 100 kHz crystal calibrator.
(2) 12AX7 A udio amp and VOX/Anti-VOX
(2) 6EA8 Mixers and oscillator stages.
12BY7A Transmitter driver stage.
6HS6 VFO premixer stage.
6AU6 VFO.
6GX6 Product detector/AM detector.
6AQ5 Audio power output.
13DE7 Audio driver and relay driver.
6EV7 Used in early production runs for relay control and driver functions (Note: Drake substituted a 6CG7/6FQ7 in later production revisions).
One 0A2 150 VDC regulation
– Diodes: 6 semiconductor diodes.
Power Requirements: Requires an external power supply capable of supplying 650 VDC at up to 500 mA peak, 250 VDC at 174 mA, -45 to -65 VDC adjustable bias, and 12.6 VAC/DC at 5.5 A. Drake offered the AC-3 supply for 120 VAC operation and the DC-3 supply for 12 VDC mobile applications. Optional accessories included the matching MS-3 speaker and RV-3 remote VFO.
