Note
QST, Jun 1962, p. 127. "Delivery by September"
QST, Oct 1963, p. 135.
QST, Jan 1964, p. 143.
QST, Sep 1964, p. 145. (now only $495.00)
The B&W 6100 was the first synthesized amateur transmitter. There were no free-running oscillators in the 6100. Its synthesizer mixed signals from two banks of 10 crystals each to cover the 80-10 meter bands. A VXO circuit was used to pull the crystals from one bank up to 11 kHz, providing continuous coverage between each of the crystal frequencies. The operating frequency was set using the band switch and the three knobs marked "kilocycles." The 6100 ran 180 watts SSB and CW, and 90 watts on AM. Operating modes include voice-operated break-in (VOX), push-to-talk (PTT), and manual control.
The defining feature of the B&W 6100 is its all-crystal frequency synthesizer, eliminating free-running VFOs entirely. It uses a 6CB6 crystal oscillator housing ten crystals spaced at 100 kHz steps (24.7 to 25.7 MHz) mixed with a second 6CB6 oscillator housing ten crystals spaced at 10 kHz steps (20.1 to 20.01 MHz). Continuous variable tuning across 11 kHz is achieved by pulling the 10-kHz step crystals downward using a variable capacitor.
A 6AH6 subtractive mixer extracts the difference frequency, outputting a stable signal between 4.7 MHz and 5.7 MHz. This signal passes through dedicated filtering and a 5763 amplifier before being fed to the second mixer stage ($V_{10}$).
The system provides dial accuracy within ±1 kHz across all bands, reset capability within ±100 Hz}, and overall drift under 100 Hz during the first 15 minutes, settling to less than 25 Hz per hour afterward.
Tube Lineup (14 total)
– 6C10 Speech amp
– 6C10 VOX amp / anti-trip amp / relay tube
– 6AL5 VOX rect / anti trip rect /
– Carrier osc
– 6BA6 3.2 MHz amp
– 6EA8 Sideband osc
– 6BA6 9.2 MHz amp
– 6CB6 Het osc
– 12AU7 1st mixer
– 12AU7 2nd mixer
– 6AL5 ALC det
– 12BY7 Driver
– (2) 6146 Final amp
References
Review: QST, Sep 1963, p. 58.
Review: CQ, Oct 1963, p. 49.
Review. 73, Nov 1963
