Regency ATC-1 RARE Mobile HF Converter in Excellent Condition

This Regency ATC-1 Mobile HF Converter in Excellent Condition. It covers 10-80 Meters and is very compact.

 I have not tested it but it looks to be in great shape. The tuning dial pointer sticks but nothing is broken.

 I am selling this Collector peice as is, as described for the family of a silent key who was my friend.

READ all about it!

The 1956 Regency ATC-1 converter heralded the dawn of a new era for amateur radio. The little converter had only two transistors -- one PNP, one NPN, both germanium, both now long obsolete -- but they were the start of a revolution. Amateurs responding to the Regency advertisement in the August 1956 issue of CQ Magazine thought they were merely buying a novel mobile converter. In truth, for $79.50, they were buying a seminal piece of ham radio history.

Regency Electronics was the brainchild of former RCA employees, Joe Weaver and John Pies. The parent company, Industrial Development Engineering Associates (I.D.E.A), was incorporated in 1947, the same year Bell Labs scientists Shockley, Bardeen and Brattain invented the transistor.

Description: The ATC-1 was intended to fill a niche market for mobile operators. When Regency introduced its new converter in 1956, most hams used dedicated receivers in their vehicles, the Multi-Elmac PMR-7, the Morrow MBR-5, and the Gonset G-66 being popular mobile receivers of the day. Other companies' mobile HF converters, such as the Gonset "tri-band Converter" had never been big sellers, primarily because their vacuum tube designs offered little space savings over full-blown receivers. Furthermore, like all mobile receivers, vacuum tube converters required an external power supply.

Regency obviously hoped that the diminuative, battery-powered ATC-1 would reverse this record. Powered by three AA penlight cells, the ATC-1 covered five bands (80-10 meters) and featured a Q-multiplier for AM reception and a BFO for SSB/CW reception. A rotating drum displayed the band in use, with single-knob tuning. Bandspread was quite adequate, with dial calibration marks every 10 kHz. The output frequency of the converter was 1230 kHz.

Despite its simplicity, the ATC-1 was a remarkable engineering achievement. To appreciate fully this achievement, however, it is necessary to place the ATC-1's design into historical context.

In the mid-fifties, the transistor's advantage over vacuum tubes was primarily in simple, portable applications, where size and power consumption were important but performance secondary. For most applications, vacuum tubes had a head start of nearly a half century, and it seemed highly improbable that transistor technology could ever catch up. Transistor usage in r.f. applications seemed particularly problemmatic.

Secondly, many engineers schooled in tube circuits found transistor circuits alien and confusing. Unlike vacuum tubes, transistors were current-operated devices. Their impedances were very low, there was little isolation between inputs and outputs, and they were prone to thermal runaway. To design with these fragile little devices, the rules of thumb, the guidelines, and the intuition developed over a professional career had to be tossed out the window. Transistors were a whole new ballgame, and the learning curve was steep.

And finally, the germanium transistors of the 1950s were unimpressive performers. Their current gain was low, as was their frequency response, and they were highly temperature sensitive. And worst of all, they were oh-so-delicate. A slip of a cliplead, a tiny snap of static electricity, a battery momentarily connected backwards, and they would be gone in an eyeblink. And to make matters worse, these early transistors cost several dollars apiece. Frankly, to many design engineers, transistors were such poor performers that using them seemed hardly worth the effort.

Against this backdrop, the ATC-1's design shines like a beacon. Consider that it used only two transistors to implement a circuit consisting of a mixer-modulator, tunable local oscillator, beat-frequency oscillator, and Q-multiplier. Furthermore, it covered the entire HF spectrum, to 30 MHz.

And the total power consumption for all this circuitry? About two milliwatts! By comparison, the Gonset mobile converter tuned only three bands, used four vacuum tubes, had no BFO or Q-mulitiplier, and required about twenty thousand times as much power.