Over the past couple of years I have been collecting some of the Heathkit monoband SSB radios. Heathkit offered several models that covered 75, 40, and 20 meters. The original HW series were LSB only. Heathkit later offered an “A” version that featured selectable LSB or USB. The frequency ranges of the HW series covered the phone portions of each band that was available at that time. View the table below for more information. The only tuning control on the radio is the PA plate tune. The plate loading capacitor is a fixed value for a 50 ohm antenna.
There was a 2 frequency radio also offered as a model HW18 that covered 4-5 mhz CAP/MARS frequencies and offered AM and SSB modes. It does not have a plate tuning capacitor. The 160 meter version was a version of this radio and marketed as the model HW18-3.
| MODEL | FREQUENCY RANGE | NOTES |
|---|---|---|
| HW12, HW12A | 3.8 to 4.0 mhz | HW12 LSB only HW12A LSB and USB |
| HW22, HW22A | 7.150 to 7.300 | HW22 LSB only HW22A LSB and USB |
| HW32, HW32A | 14.200 to 14.350 | HW32 LSB only HW32A LSB and USB |
| HW18-1 | 4.450 to 4.650 CAP FREQUENCIES | 2 Crystal controlled frequencies - Selectable AM/USB |
| HW18-2 | MARS Frequencies - 4 to 5 mhz? | 2 Crystal controlled frequencies - Selectable AM with sideband determined by carrier oscillator crystal frequency. |
| HW18-3 | 1.800 to 2.000 | 2 crystal controlled frequencies - Selectable AM/LSB |
All HW monoband radios used the HP23 series of supplies or other compatible power supply. The monoband radios require 250-275 vdc on the medium HV. HW100/101 and other Heathkits required 350 vdc. Some of the HP23 supplies have a 3 position on/off/on switch which selects the correct tap on the transformers. HP23 supplies that do not have this center “OFF” position must be operated with the 275 v tap connected to the medium HV if using with one of the monoband series radios. If you choose to operate the radio at the higher medium voltage, circuits will be detuned, performance will suffer, and some components could be damaged.
The HW12, 22, 32 all use 2305khz as the IF frequency. A digital frequency display can be used on the radio if it will offset the required 2305khz (+or-) with the VFO signal collected from the VFO buffer amplifier tube cathode.
The HW18 uses 3396.5 KHz as the IF frequency in a USB model and 3393.5 khz in a LSB model. Control crystal frequencies from 7.840 to 8 mhz range for the -1 and -2 models. The -3 used control crystal frequencies of 5.2 to 5.4 mhz and used the LSB 3393.5 khz IF. AM operation does not have a high duty c
Refurbishment of the radios I have acquired have been pretty simple. Heathkit used several Mylar type 100 volt rated capacitors across cathode resistors in most radios and some of mine have shown a lot of cracking in the outer coating. One of my radios had ceramic disc capacitors in place of mylar. They also used 3 .47 uf capacitors that may or may not be suspect. Make sure you check cathode resistors as some will have changed values out tolerance. Resistors that seem to be out of tolerance the worst are 100K, 220K, and 2.2 meg. Inspect the tube socket pin soldering as some may not be done well and any suspect joints should be touched up.
An HW12 that crossed my bench had intermittent issues with all of the 7 pin tube sockets not retaining the tubes well. If you turned the radio upside down, a couple would fall out. I replaced all of the 7 pin tube sockets with new ones. A HW12A did not RX or TX. The carrier oscillator crystals are attached to the terminals of a DPDT slide type switch and the issue was traced there. One crystal did not have one lead soldered to the switch (builder omission) and both crystals had broken solder joints on the leads. Resoldering restored the radio to working order. On another, the meter switch required treatment with Deoxit to restore the contacts to make the meter work.