Note
In 1966 Heath revisited the Single-Banders and made a few significant changes, though the basic specifications of the A series of Single-Banders are identical to the originals.
Most of the changes are related to operating convenience. Refer to HW-12 for a discussion of basic features.
The following is a discussion of the changes found in the “A" series radios. Most notable among these changes are the microphone connector and mic gain control, which have been moved from the rear apron to the front panel along with the bias adjust control. Conversely, the VOX sensitivity control has been moved from the front panel to the rear apron, to which a VOX delay control has been added. The tune level control remains on the rear apron. Another significant change in the A series was the addition of a switch allowing the units to run both upper and lower sideband.
Other changes include the addition of a position on the function switch for on/off control of the crystal calibrator and the replacement of the octal power plug with an 11-pin plug. The “A" series also was restyled with a new paint scheme. While the two-tone green color remains the same, dark green now surrounds the tuning window and main tuning knob, and the smooth finish of the originals has been replaced with the wrinkle finish that had become Heath’s new standard paint. New knobs are used as well. They are the same knobs used by the SB line—dark green with polished chrome skirts.
A more subtle change is that the rear panel EXT RELAY jack of the HW-12 has been replaced with an ALC jack, so that the “A” series transceivers are plug-and-play compatible with the HA-14, SB-200(201) and SB-220(221) amplifiers. (The relay contacts are available on the 11-pin plug.)
A Turner 350C hand microphone was optional. Refer to GH-12 for more information.
Among the Single-Bander rigs, the A versions are generally more plentiful than the originals, and among the A versions, 80-meter units are seen more often than 40s or 20s. Beware all kinds of strange modifications. Note: The HS-24 matching mobile speaker makes a fine companion for the Single-Banders.
POWER PLUG CONNECTIONS
Pin 1: bias (–130 volts)
Pin 2: filament common
Pin 3: LV B+ (250 volts)*
Pin 4: HV B+ (800 volts)
Pin 5: n.o. relay
Pin 6: filament (12 VAC)
Pin 7: ground
Pin 8: nc
Pin 9: switch (120 VAC)
pin 10: switch (120 VAC)
pin 11: n.o. relay
*Caution: Run only at 250 VDC B+.
References:
Better dial mechanism. QST. Jun 1968, p. 36.
Noise limiter. Ham Radio. Mar 1971, p. 67.
Use on MARS. Ham Radio. Sep 1971, p. 63.
VFO slippage and backlash. QST. Sep 1976, p. 39.
A receiver pre-amp for. CQ. Mar 1976, p. 26.
Receiver Section
Frequency coverage: 3.8 to 4.0 MHz
Receiver mode: lower or upper sideband
Sensitivity: 1.0 µV input will provide at least 15 db signal plus noise to noise ratio
Selectivity: 2.7 kHz @ 6 db, 6 kHz @ 50 db
IF: 2305 kHz
Image rejection: 100 db
IF rejection: 50 db
Receiver audio response: 400 to 3000 Hz
Receiver audio power output: 1 watt
External speaker impedance: 8Ω
Antenna input impedance: 50Ω nominal, unbalanced
Transmitter section
Frequency coverage: 3.8 to 4.0 MHz
Transmitter mode: lower or upper sideband
Stability: less than 200 Hz per hour after one-hour warmup
RF power output: 200 watts PEP
Unwanted sideband suppression: 45 db minimum below peak output @ 1000 Hz
Carrier suppression: 45 db minimum below peak output
Output impedance: 50Ω nominal, unbalanced
Transmitter audio response: 400 to 3100 Hz
Microphone required: hi-Z crystal, ceramic or dynamic; 10 mV minimum output
Power requirements: 800 VDC at 250 ma, 250 VDC at 100 ma, -125 VDC at 5 ma, and 12 volts AC or DC at 3.75 amps
Size: 12.25 wide x 6.25 high x 10 deep; Weight: 12 lbs
Tubes: (3) 6EA8, (5) 6AU6, (1) 6BE6, (1) 12AT7, (1) 12BY7, (1) 6EB8,
(2), 6GE5
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.
