Note
73, Sep 1961, p. 29.
QST, Jul 1962, p: 123.
Herb Johnson, then W7GRA, built the first Swan transceivers in his Benson, Arizona garage. They were single-band affairs, and the first ones completed were SW-120 models for the 20 meter band. The 40 meter SW-140 and SW-175 for 75 meters followed. The transceivers' VFOs covered the phone portion of their respective bands.
These single band transceivers predate similar units from Heath by about a year, and appeared concurrently with similar units made by Sonar.
SW-175 3.8-4.0 MHz LSB
SW-140 7.2-7.3 MHz LSB
SW-120 14.2-14.35 MHz USB
SW-115 21.25-21.45 MHz USB (either never made, or discontinued quickly)
– Input power: 240 watts PEP input to 6DQ5 Power Amplifier.
Note: the original ad (Sep 61) listed in the input power as 130 watts.
– High frequency crystal lattice filter: 3 Kc. nominal bandwidth, used for both transmit and receive.
– Unwanted sideband down approximately 40 db. Carrier suppression approximately 50 db.
– Receiver sensitivity better than 1 microvolt at 50 ohm input.
– Audio response from 300 to 3,000 Hz.
– Main Tuning: 16:1 tuning ratio. Calibrated in 2 Kc. increments.
Transceiver produces approximately 25 watts carrier output on AM by adjusting the Carrier Balance control. "Receives AM signals very satisfactorily."
Based on the technical specifications and parts lists provided in the document, here is the complete list of tubes (tube complement) utilized in the Swan SW-100 series transceivers:
– 6DQ5 Power Amplifier (P.A.)
– 12BY7 or 12BY7A Driver
– 12BE6 Transmitter Mixer
– 12AU6 Voltage Regulated Oscillator (VFO)
– 6BA6 Receiver RF
– 12BE6 Receiver Mixer
– 6BZ6 (or 6BA6) 1st IF Amplifier
– 6BA6 2nd IF Amplifier
– 7360 Balanced Modulator
– 6V6GT Audio Frequency (AF) Output / Amp
– 12AU7 Microphone Amplifier
– 12AX7 Product Detector / AF Amp
– 6BA6 Carrier Oscillator
– 0D3 Voltage Regulator
– 12AV6 Audio Frequency (AF) Oscillator
Power Requirements:
275 volts DC, nominal, at 90 ma., receive and transmit.
650 volts DC, nominal, at 25-200 ma., transmit only.
80 volts DC, negative bias, at 6 ma., receive and transmit.
12.6 volts AC or DC at 3.45 amperes, for filaments.
References
Review: QST, Aug 1962, p. 52.
Adding a second band. 73, Jul 1963, p. 18.
Converting the SW-120 to 2 meters. 73, Jul 1965, p. 52.
Converting the Swan 120 to 2 meters. Ham Radio, May 1968, p. 8.
