Yaesu FT-101


Yaesu FT-101 is a model line of modular amateur radio transceivers, built by the Yaesu Corporation in Japan during the 1970s and 1980s. FT-101 is a set that combines a solid state transmitter, receiver and a tube final amplifier. Its solid state features offer high-performance, low-current characteristics and its tube amplifier provides an almost mismatch-resistant transmitter and tuner stage. FT-101’s were made with plug-in circuit boards that could be sent to the dealer or factory for replacement or repair. Until then, modular design was unprecedented in the amateur community. This also explains the fact why so many FT-101's are still in use today. The rig was sold worldwide as Yaesu FT-101 and in Europe as Yaesu FT-101 and as Sommerkamp FT-277. Because of its reliability it earned its nickname "the workhorse".

Technical description

The original FT101 Series had dual conversion, with 5 MHz Receiver first IF, a very stable and linear 9 MHz VFO and 3.2 MHz 2nd IF. They had a 12BY7A tube driver feeding two 6JS6C television sweep tubes providing a nominal output power of 130 watts peak envelope power in single sideband, 90 watts continuous wave and 40 watts amplitude modulation. The 6JS6C tubes are matched to the antenna through a conventional pi network. This transforms 3000 ohm output impedance of the tubes to a low impedance, typically 25 to 200 Ohms. These tubes were common to television sweep circuits in the day, and were in practice just as rugged and reliable in amateur service as genuine transmitter tubes such as the 6146.
These rigs were extremely reliable, and various improvements were made over the model range, especially to the receiver, from Mk1, Mk2, B and E models. This was also one of the first all-in-one box rigs, as it had a built-in AC Mains and 12V DC inverter power supply and even a loudspeaker, which made it ideal to use portable. They also included two switched crystal-controlled positions for Novice license holders, who were restricted to crystal controlled transmission until the late 70's. This feature was also required for Maritime Mobile operation.
All models after the Mk1 came with a PA fan, and the E models had a built-in RF Speech Clipper.
The FT101 was virtually the only rig that had adjustable temperature compensation in the VFO, when properly adjusted it is extremely stable. An outboard Digital Display was available, the YC601.
Thousands of these transceivers are still going strong today, as even if any parts do fail, they are readily replaceable with standard components. Sherwood Engineering lists this rig as having one of the most sensitive and quietest receivers of any rig.
Yaesu also brought out a pair of separates, using almost every circuit from the FT101 - the FR101 Receiver and FL101 Transmitter.
The Later FT101Z series was a completely different rig, much more cheaply engineered. It was single conversion from a 9 MHz IF, lower power PA tubes and no plug-in circuit boards. It also came without a 12V inverter power supply.

Specifications

The unit could receive from 10.0-10.5 MHz in order for reception of the WWV time and frequency standards. The unit could transmit and receive on the 160 m, 80 m, 40 m, 20 m, 15 m, and 10 m amateur radio bands. WARC band coverage was possible using aftermarket kits. All FT101 models covered the 11 metre band, but for the USA market the band crystal was often removed as well as the 11m link cut on the Driver bandswitch wafer. The Mk2, B, E, and F versions included reception and transmission on the 160 meter band, as well. Although the Mk1 did not cover 160M, there was an AUX band position, and some Yaesu dealers offered a 160M modification.
The unit can modulate using either upper sideband, lower sideband, continuous wave, or amplitude modulation. The power available in these modes is 130 W, 90 W, 40 W. The standard I.F. crystal filter used for transmission passed 300 Hz to 2700 Hz.

Accessories

Many station accessories were available including the FV-101 remote VFO,FL-2100 Linear Amplifier, SP-101PB Phone Patch with Speaker or SP-101 Speaker-only, YO-100 or YO-101 Monitor Scope, YC-601 Digital Display Unit, FTV-250 2 Meter Transverter, FTV-650 6 Meter Transverter, YP-150 Dummyload / Watt Meter, YD-844 Dynamic Desk Microphone and QTR-24 World Clock

Models

Many models in the FT-101 series were manufactured in its timeline:
Because critical circuit designs were kept to a manageable size, hams had no problem in offering circuit changes, isolating and repairing problems. This knowledge base was so active that in January 1972, Milton Lowens, founded the International Fox Tango Club and the Fox Tango Newsletter. The Fox Tango Newsletters were published for 14 years covering the early FT-101s through the latest Yaesu transceivers in 1985.
This HF radio was the same model used by Jim Jones in Jonestown before the 1978 mass suicide.