Note
QST, Oct 1977, inside back cover.
QST, Jan 1979, p. 205. (FT-227RA – with AutoScan, 4 memories)
QST, Jun, 1979, p.122. (FT-227RB)
QST, Jan 1980, p. 163.
The Yaesu "Memorizer" is a solid-state, fully synthesized 800-channel 2-meter FM transceiver.
Features
– Frequency Coverage & Control: Operates across the 144–148 MHz two-meter amateur band in 5 kHz steps using Phase-Locked Loop (PLL) synthesis. Frequency selection utilizes an innovative photo-optic sensor to eliminate mechanical switch wear and problems. Frequency readout is displayed via four large LEDs.
– Memory Circuit: Features a special memory circuit that allows the operator to instantly return to any preselected channel with the flip of a switch. It accommodates standard ± 600 kHz offsets as well as any custom/odd splits within the 2-meter band.
– Transmitter & Receiver Performance: Offers selectable 10-watt or 1-watt RF output. It includes automatic final protection, PLL unlock protection, a busy channel indicator, built-in tone burst, and an optional tone squelch-decoder. Spurious emissions are well below the minus 60 dB requirement, with strong cross-modulation, overload, and image rejection.
– Power Requirements: Operates on 13.8 V DC (± 10%), drawing approximately 800 mA on receive and 2.5 amps on transmit.
Specifications
– Type: Synthesized 2-meter FM transceiver (completely solid-state).
– Frequency Range: 144.00 MHz to 147.99 MHz.
– Channel Capacity / Steps: 800 digital Phase Lock Loop (PLL) channels in 5 kHz steps.
– Frequency Display: Digital LED display showing frequency in MHz, 100 kHz, and 1 kHz.
– Frequency Tuning: Optical coupling system (eliminates mechanical rotary switches).
– Memory & Offsets: Built-in memory circuit to store any selected channel. Standard -600 kHz repeater split, +600 kHz split, or programmable ODD split frequency repeater operation.
– Modulation Type: Frequency Modulation (FM) via phase modulator varactor diode.
– RF Power Output:
HIGH: 10 Watts into a 50 ohms load.
LOW: 1 Watt (adjustable via VR206)
– Frequency Deviation: Nominally set for ± 5 kHz maximum deviation.
– Tone Burst Generator: Built-in, fully adjustable for pitch (VR207), duration (VR208), and output level/deviation (VR209).
– Protection Circuitry: Automatic protection circuit lowers power output if keyed without an antenna or if high VSWR is detected.
– Receiver Type: Double conversion superheterodyne.
– Intermediate Frequencies (IF):
1st IF: 10.7 MHz (passband of 7.5 kHz via crystal filter)
2nd IF: 455 kHz (utilizes ceramic filters)
– Front End: Dual-gate FET RF amplifier coupled with 4-stage high-Q coaxial resonators.
– Audio Filter: Low-pass filter attenuates frequencies above 3 kHz to enhance readability.
Optional Equipment / Features
– Tone Guarded Squelch (TGS / PB-1555A):
Allows silent monitoring by opening squelch only upon receiving a preset tone.
– Selectable tone frequency range: 70 Hz to 250 Hz (specifically 160 Hz to 250 Hz for standard sub-audible operation).
– Includes a BUSY indicator lamp that lights up when a carrier is present, even if squelched.
Power Supply Requirement: 13.8 V DC ± 10%, negative ground.
