YAESU FT-227R Memorizer 2 Meter FM Transceiver User Manual

General Information

The YAESU FT-227R is a new synthesized 2 meter FM transceiver designed for high performance in amateur VHF/FM communications. It utilizes Yaesu computer theory and is completely solid state, offering 800 digital Phase Lock Loop channels in 5 kHz steps between 144 to 148 MHz. An "optical coupling" system eliminates noisy rotary switches. The digital LED display shows the selected channel in MHz, 100 kHz, and 1 kHz, providing clear readability even in bright sunlight.

The transceiver features a memory circuit that stores any of the 800 channels, allowing instant recall with a touch of a switch. It supports conventional ±600 kHz repeater split, and any transmitter offset frequency can be memorized for operation on ODD split frequency repeaters. A built-in tone burst generator is fully adjustable for pitch, duration, and level, enabling tone burst accessed repeater operation.

An optional tone guarded squelch (TGS) provides silent monitoring. In TGS mode, a tone guarded signal automatically opens the receiver squelch circuit. The tone frequency is selectable from 160 Hz to 250 Hz. The BUSY lamp indicates if a channel is occupied or acts as an alarm if receiver volume is too low.

Advanced circuit design prevents damage from high antenna VSWR or reversed power supply polarity. The FT-227R is manufactured with a diecast front panel and heavy gauge metal case for extreme ruggedness, minimizing shock and vibration effects. Channels can be limited to 400 within either 144-146 MHz or 146-148 MHz. The FT-227R VHF/FM transceiver comes complete with all mounting hardware, cables, connectors, and accessories for mobile installation.

Included Accessories:

1. Transceiver with built-in 3" speaker.
2. Dynamic push-to-talk microphone with retractable coiled cord.
3. Universal mounting bracket (with screws, washers and nuts).
4. Power cable.
5. Cigarette lighter adapter.
6. Spare fuses.
7. Microphone hanger.
8. Miniature phone plug for external speaker.
9. Accessory plug.
10. Tap connector.

How to Use the Tap Connector

The tap connector is designed for automotive instrument panel wires. Do NOT strip insulation from wires. Slice the "hot" lead into the tap connector. Insert the transceiver power lead 3/4 of the way into the connector (past the metal connector element). Use pliers to press the metal connector element until it is FLUSH. Fold the hinged cover over the connector element and snap firmly in place. This self-stripping "U" type spring pressure connector element makes connection with any pliers-type tool by driving the element over the wires. The compact design of the FT-227R makes it ideal for mobile installation, operating directly from a vehicle's 12 Volt battery. For base station use, an AC Power Supply rated 2.5 ampere at 13.8 V DC is required.

Specifications

General

• Frequency Coverage: 144 to 148 MHz
• Number of Channels: 800 channels
• Speaker: Internal 3" dynamic speaker with provision for connecting an external 8 ohm dynamic speaker
• Microphone: Dynamic push-to-talk microphone with retractable coiled cord.
• Power Requirement: 13.8 Volts DC, ±10%
• Current Consumption: 0.5 Amps Receive, 1.0 Amps Transmit (LOW), 2.5 Amps Transmit (HI)
• Metering: Illuminated front panel meter indicates relative received signal strength and transmitter power output
• Dimensions: 180 (W) x 60 (H) x 220 (D) mm
• Weight: 2.7 kg.

Transmitter

• RF Output: 10 Watts (HI) or 1 Watt (LOW) into 50 ohms load at 13.8 Volts DC
• Frequency Stability: ±0.002%
• Modulation: F3
• Deviation: ±5 kHz
• Audio Response: +1, -3 dB of 6 dB/Octave pre-emphasis characteristic from 300 to 2500 Hz
• Spurious Emissions: 60 dB below carrier minimum
• Tone Burst: Nominally one second at 1800 Hz
• Repeater Split: ±600 kHz or any frequency in 5 kHz increments

Receiver

• Type: Double conversion super-heterodyne
• Intermediate Frequency: 10.7 MHz first IF; 455 kHz second IF
• Sensitivity: 0.3 µV for 20 dB quieting
• Selectivity: ±6 kHz at 6 dB; ±12 kHz at 60dB
• Audio Output: 1.5 Watts at 8 ohms

Installation

General

The FT-227R transceiver is designed primarily for mobile service, requiring only an antenna and a 13.8 Volt DC power source. The transceiver is factory pre-tuned and requires no adjustments for normal operation into a 50 ohm load.

Antenna location is crucial for effective communication range. The antenna should be in the clear and as high as possible, maintaining a minimum distance of 5 feet between VHF and other antennas. For mobile installations, locate the antenna as far from the engine as practical to minimize ignition noise pick-up. Ensure the antenna VSWR is less than 1.5:1.

Popular mobile antenna types include 1/4 wave length whip with unity gain or 5/8 wave length with approximately 3.5 dB gain. To minimize losses, use the shortest practical length of coaxial cable, avoiding sharp angles or kinks. Use type RG-8/U cable for transmission line lengths exceeding 25 feet, and RG-58U for shorter lengths. For all bends, form the cable into a radius of not less than 10 times its diameter.

Mobile Installation

Install the FT-227R where controls, indicators, and the microphone are easily visible and accessible. Suitable locations include under the dash or atop the transmission tunnel. A universal bracket is supplied for this purpose.

1. Use the universal mounting bracket as a template to locate mounting holes. Use a 3/16" diameter drill for these holes, allowing clearance for the transceiver, its controls, and connecting cables. Secure the mounting bracket with the supplied screws, washers, and nuts.
2. Install the transceiver in the mounting bracket by sliding it into the guide rail and tightening the screws on both sides.
3. The microphone hanger can be affixed to any convenient place for handling the microphone.
4. The supplied power cable can be plugged directly into the vehicle's cigarette lighter receptacle for casual operation. For permanent installation, remove the lighter plug and route leads directly to the battery (red positive, black negative or ground), or the nearest termination (ignition switch, fuse block). If extending power leads, use #16AWG insulated copper wire and do not extend further than required to avoid excessive voltage drop. Note: Frequency may shift to 147.000 MHz or 147.005 MHz if supply voltage is accidentally opened by a loose power adaptor contact.

5. Connect the power cable to the POWER receptacle on the rear panel.
6. Connect the 50 ohm antenna cable to the ANT receptacle on the rear panel.
7. Connect the microphone cable to the 4-pin microphone receptacle on the front panel.
8. An external 8 ohm speaker may be connected at the SP receptacle on the rear panel (this automatically disconnects the internal speaker). Use the external speaker plug supplied.

Base Station Installation

As a base station, the FT-227R requires a source of 13.8 Volts DC at 2.5 amperes.

Controls & Switches

The FT-227R is designed for ease of operation, though some controls may be unfamiliar due to its modern computer technology. Understand each control and indicator before operating.

Front Panel Controls:

1. Channel Selector: Endless optical coupling selects 800 channels.
2. VOL inner control: Adjusts the receiver audio output level and turns power off when rotated to an extreme counter-clockwise (CCW) position.
3. SQL Outer control: Adjusts the receiver squelch threshold sensitivity.
4. FUNCTION Switch: Selects the transmitting frequency:
   • SIMP: Simplex operation.
   • +600: Transmitting frequency is 600 kHz higher than the receive frequency.
   • -600: Transmitting frequency is 600 kHz lower than the receive frequency.
   • MEM: Transmit on memorized frequency.
5. DIAL Display: Digital display indicates the operating frequency.
6. METER: Indicates signal strength on receive and relative power output on transmit.
7. MIC receptacle: Four pin connector for microphone input and push-to-talk relay actuation.
8. MEMORY switch: When pressed, the dial frequency is memorized and the 'M' lamp lights up. Press a second time to release the memorized frequency.
9. 5UP switch: Shifts the channel frequency 5 kHz up, and the '5UP' lamp lights up.
10. TONE SQUELCH switch: Activates an optional TONE SQUELCH circuit when pressed, and the 'TONE SQ' lamp lights up.
11. MEMORY RECALL switch: When pressed, the memorized frequency is recalled and the 'MR' lamp lights up.
12. BUSY indicator: Lamp lights up when a signal is received.
13. ON AIR indicator: Lamp lights up when in the transmit mode.

Rear Panel Controls:

1. POWER receptacle: A two-pin connector for 13.8 Volts DC (negative ground) power source, vehicle battery, or AC power supply.
2. SP receptacle: Audio output for an external speaker (8 ohms impedance). Inserting a plug disables the internal speaker.
3. ACC socket: Used for external control of the transceiver.
4. BURST switch: Applies a short "tone burst" to the carrier at the start of each transmission in the "ON" position. Used with "tone access" repeater actuation.
5. HI/LOW switch: Selects desired RF power output: 10 Watts in HI position or 1 Watt in LOW position.
6. ANT receptacle: UHF type coaxial receptacle for antenna connection.

Operation

Initial Check

1. Rotate the VOLUME control clockwise to apply power. The meter will illuminate, and the channel frequency automatically sets to 147.000 MHz (with 5 kHz up at depressed position), regardless of channel knob position. A memorized frequency can be retained if the MEMORY switch is left depressed.
2. Rotate the SQUELCH control fully counter-clockwise.
3. Adjust the VOLUME control for a normal listening level (background noise or a transmitting station).
4. When the channel is clear (background noise only), rotate the SQUELCH control clockwise until the receiver is silenced and the busy lamp turns off. Perform this carefully to avoid going beyond the silencing point, which would prevent the receiver from responding to weak signals.
5. Set the HI-LOW switch on the rear panel to the desired power output position.

Frequency Selection

The channel select knob adjusts the frequency in 10 kHz steps. Clockwise rotation increases frequency up to 148.000 MHz; counter-clockwise rotation reduces it down to 143.990 MHz. Pressing the 5 kHz up switch shifts the channel frequency 5 kHz higher. On 148.005 MHz and 143.990 MHz, the transmitter section is automatically disabled to prevent transmission outside amateur bands.

Memory Operation

Select the desired channel with the channel select knob. Press the M (Memory) switch; the M lamp lights up, indicating the channel is memorized. The memorized frequency shifts 5 kHz up when the 5UP switch is pressed and shifts down when released. After memorizing, the channel selector knob can be used to select other frequencies. To recall the memorized frequency, press the MR (memory recall) switch.

The MR lamp lights up, and the memorized frequency is displayed. Pressing the MR switch again returns to the frequency preset by the channel selector knob. The channel selector knob can then be used to select a new frequency. To release the memorized frequency, press the M switch again.

The memorized frequency is retained when power is turned off by the front panel switch but disappears if the power cord is removed. The memory circuit functions with the FUNCTION switch in any position. When the FUNCTION switch is in the MEM position, the MR switch is inoperative, and the memorized frequency is transmitted by the PTT switch.

Repeater Operation

The transmitting frequency can be shifted for repeater operation. When the FUNCTION switch is set to +600 kHz, the transmitting frequency shifts 600 kHz up from the displayed receive frequency. With the FUNCTION switch at -600 kHz, the transmitting frequency shifts 600 kHz down.

The MEMORY function can be used with the function switch on the repeater position, and the receive frequency is memorized.

For non-standard offset, first memorize the transmit frequency. Then find the receive frequency using the channel selector knob. Set the FUNCTION switch to MEM position. The transceiver will then transmit on the memorized frequency and receive on the frequency displayed in the channel window.

If operating on a repeater channel requiring "tone access," set the BURST switch on the rear panel to the "ON" position. The "tone burst" will be applied to the carrier each time the push-to-talk lever on the microphone is depressed.

When ready to transmit, hold the microphone close to your mouth, depress the push-to-talk lever, and speak distinctly at a normal conversation level. Check that the red "transmit" indicator illuminates and the meter indicates upward.

FT-227R Memorizer Block Diagram

The FT-227R block diagram illustrates the interconnected main unit, PLL unit, display unit, and optional tone squelch unit. The main unit comprises transmitter and receiver sections. The transmitter processes audio signals from the microphone, modulates them, and amplifies them for RF output. The receiver section handles incoming RF signals, converts them through double conversion super-heterodyne stages, and outputs audio. The PLL unit generates stable frequencies for both transmit and receive operations, controlled by a programmable divider and phase comparator. The display unit shows the operating frequency, driven by BCD signals from the PLL control section. The optional tone squelch unit integrates with the audio path for private communications. Power distribution and various control lines ensure proper operation and protection circuits are also depicted.

Theory of Operation

This section provides a detailed understanding of the transceiver's block diagram and circuit. The FT-227R consists of a transmitter and a double conversion super heterodyne receiver, utilizing a digital phase lock loop synthesizer, capable of operating on any of the 800 channels within the 144 to 148 MHz frequency range. It features solid-state circuitry and computer theory for frequency selection, operating from a 13.8 Volts ±10% negative ground power source.

Transmitter

The transmitter produces a Frequency Modulated (FM) signal. The audio signal from the microphone is leveled by VR201 and amplified by Q201, Q202, and Q203 (2SC372Y). The audio output from Q202 is coupled to the IDC (Instantaneous Deviation Control) circuit, where positive and negative peaks are clipped by D201 and D202 (1S1555). The output from Q203 is fed through a low-pass filter, attenuating frequencies above the speech range. This signal is then applied to a phase modulator varactor diode, D401 (ISV50), which varies the frequency of the 10.7 MHz crystal controlled oscillator, Q401 (2SC372Y).

The frequency modulated 10.7 MHz signal is amplified by buffer Q402 (2SC372Y) and fed to a balanced mixer (Q403 and Q404, 2SK19GR) where it is converted up to 144-148 MHz by mixing with the 133.3-137.3 MHz signal from the VCO. The output from the balanced mixer is fed through tuned circuits (T404-T407) to amplifier Q405 (35K40M). T404-T407 are tuned to the transmitting frequency by varactor diodes D403-D406, whose capacitance changes with the DC output voltage from the PLL circuit. The 144-148 MHz signal is then amplified by stages Q204 (25C535A), Q206 (2SC2053), Q207 (2SC730), and Q208 (MRF212), delivering 10 Watts of RF energy through a diode switch and low pass filter into a 50 ohm load.

Diodes D205 and D211 (1S188FM) rectify a portion of the RF output, applying the resultant DC voltage to the meter for power output indication. This DC output also drives lamp driver Q209 and Q210 (2SC372Y), which illuminates the ON AIR lamp during transmission.

If the transmitter is keyed without an antenna or with high VSWR, reflected power is detected through T202 and D208 (1S188FM), producing DC voltage. Q211 (2SC372Y) conducts, decreasing Q212 (2SC372Y)'s collector current. This drops Q213 (2SA496)'s collector voltage, causing Q11 (2SD235) to decrease current and supply voltage to the PA amplifier, preventing transistor damage. The threshold is set by VR205. This circuit also switches output power to 1 Watt when the HI-LOW switch is set to LOW, adjustable with VR206. The antenna change-over circuit uses switching diodes D206 and D207 (M1301).

The tone burst circuit includes a timing generator and a gated multivibrator. With the BURST switch "ON," DC voltage is applied to the tone burst circuit. When the transmitter is keyed, Q214 (2SC372Y) conducts and triggers the one-shot multivibrator Q215 (MC140ilB). The other half of Q215 generates a tone signal, amplified by buffer Q216 (2SC372Y), and applied to the microphone circuit. Tone frequency is adjustable by VR207, output level (deviation) by VR209, and burst duration by VR208.

Receiver Section

The input signal from the antenna passes through a low-pass filter (L1, L214, L213, C1, C243-C245) and diode change-over switch (D206, D207, L212) to the FET amplifier Q101 (3SK51). The amplified signal then goes through four high Q coax resonators to the first mixer Q102 (3SK51). The dual gate FET RF amplifier and high Q coax resonators minimize cross modulation and spurious responses, providing a low noise figure.

The 144 to 148 MHz signal is heterodyned with the first local oscillator, producing a 10.7 MHz first IF signal. The first local oscillator is from the PLL (Phase Lock Loop) VCO circuit. The first IF signal is fed through a crystal filter XF101 (pass band -7.5 kHz) to the second mixer Q103 (3SK40M), which produces a 455 kHz second IF signal by heterodyning with the 10.245 MHz output of the second local oscillator Q104 (2SC372Y). Q105 (2SA564) acts as a switch, disconnecting supply voltage to Q104 when the PLL circuit is unlocked.

The second IF circuit consists of Q106, Q107, Q108 (2SC372Y) and Q109 (µPC577H). Cascade connected ceramic filters CF101 and CF102 provide narrow band selectivity, and Q109's limiting action removes amplitude variation to the ceramic discriminator (CD101, D106, D107, 1S188FM). The discriminator produces audio output from frequency shifts in the IF signal. This audio is amplified by Q113, Q114 (2SC372Y) and applied across the VOLUME control VR1 to the audio amplifier Q116 (µPC575C2). The output from Q116 is applied in series through the ACC socket to the internal speaker. A low-pass filter between Q113 and Q114 attenuates audio frequencies above 3 kHz to increase readability.

A portion of the 455 kHz IF signal is rectified by D103, D104 (1S188FM) for S-meter indication, with VR101 adjusting sensitivity. When no carrier is present, high frequency noise at the discriminator output is amplified by Q110 and Q111 (2SC372Y), then detected by D108 and D109 (1S188FM) to produce a DC voltage. This voltage turns Q112 (2SC372Y) on, grounding Q113's base to squelch the audio amplifier. When a carrier is present, noise is removed, and the audio amplifier recovers. The squelch circuit opening causes Q113 to conduct, drawing current through lamp driver Q115 (2SC372Y) to light the BUSY LAMP. SQUELCH controls VR2 and VR102 set the threshold level.

Heterodyne Oscillator

The heterodyne signal is generated by the PLL (phase lock loop) circuit, comprising a VCO (voltage controlled oscillator), reference crystal oscillator, programmable divider, and phase comparator. The VCO oscillator, Q301 (2SK19GR), generates 133.3-137.3 MHz signals. Its frequency is controlled by varactor diode D301 (1S2209), which varies the capacitance of a tuned circuit (L301, TC301, C302, C304) according to a DC voltage from phase comparator Q309 (TC5081P).

The output from Q301 is amplified by buffer amplifiers Q302 (3SK40M) and Q303 (2SC535A) and fed through a diode switch (D302, D303, 1S1555) to the receiver or transmitter mixers.

A portion of Q303's output feeds buffer amplifier Q304 (3SK40M) to PLL mixer Q305 (2SC535A), producing 1-5 MHz PLL IF signals by mixing with the PLL heterodyne signal. The PLL heterodyne signal is generated by overtone crystal controlled oscillator Q310 (2SC373). The crystal frequencies are:

Diode switch D315-D320 (1S1555) selects the appropriate crystal based on the FUNCTION switch and 5kHz up switch. Q310's output feeds tripler Q311 (2SC710), which produces the PLL heterodyne signal. The PLL IF signal passes through a low pass filter (L305, C331, C332) to amplifiers Q306 and Q307 (2SC372Y). The amplified signal then feeds programmable divider Q308 (uPD857C).

Crystal oscillator Q312 (2SC373) generates a 10.24 MHz signal, feeding scaler/divider Q308 (uPD857C) to produce a 10 kHz reference signal. Digital phase comparator Q309 (TC5081P) compares the PLL IF signal phase with the reference signal, converting any phase difference into an error correcting voltage. This voltage feeds varactor diode D301, changing its capacitance to lock the output signal phase with the reference signal.

When the VCO is locked, constant voltage at pin 4 of Q309 is applied to Q316 (MPSA13) to conduct, cutting off Q315 (2SC372Y). The "H" voltage at Q315's collector turns Q205 (2SC372Y) to conduct, supplying DC voltage to exciter stages Q204 and Q206. When the VCO is unlocked, Q205's emitter DC voltage drops, preventing normal operation of Q204 and Q206.

Q315's output voltage is reversed in polarity by Q314 (2SC372Y) and applied to Q606 (2SC372Y), keeping Q606's collector at "H" level to drive Q601-Q603 for channel frequency display. This voltage also applies to Q105 (2SA564), supplying DC voltage to second heterodyne oscillator Q104 (2SC372Y). When the VCO is unlocked, collector DC voltage drops, turning off LEDs and stopping the second heterodyne oscillator, muting the receiver until VCO lock occurs.

PLL Control Section

The optical coupling system uses two photo-interrupters Q2 and Q3 (PS-4001) to generate two signal outputs for the PLL counter unit. The signal to the CK terminal is fed through waveshaper Q710 (MC14049B) to BCD up/down counter Q707 (10 kHz), Q708 (100 kHz), and Q709 (1 MHz), using MC14510B as a clock signal. The signal to the U/D terminal is inverted by Q710 and controls the up/down counter. The output from Q707-Q709 feeds a 4-bit data selector Q701-Q703 (MC1451B) and Quad latch Q704-Q706 (MC14042B), used for memory when the MEMORY switch is pressed. The output from Q701-Q703 feeds programmable divider Q308 (µPD857C).

Q711 (MC14081B) for high end and Q712 (MC14028B) for low end cut off Q713 (2SC735Y) to prevent transmission outside amateur bands. BCD signals at the programmable divider input also feed LED driver Q601-Q603 (MSM561) to drive LEDs D601-D603 (TLR 312). A 4-BIT full adder Q604 (MC14008B) produces a 4-8 display on MHz range. LED D604 (TLR312) displays 0 or 5 via the 5 UP switch. The display LED turns off via Q605 (2SC372Y) when an unlocked signal is received.

Power Supply

A DC 13.8 Volt supply powers the audio power amplifier Q116, relay, and lamps. Supply voltage to the driver and final power amplifier is regulated by Q11 (2SD235D), controlled by the HI/LOW switch and automatic final protection. Voltage regulator Q605 (µPC14305) regulates 5 Volts for Q308 and the display unit. Q313 (2SC372Y) and D301 (RD6.8EB) regulate 6 Volts for the VCO and phase comparator. The 5 Volts supply for the PLL control unit is regulated by zener diode D3 (WZ050) and is connected directly to keep memory when the power switch is off and M switch is pressed. A regulated 8 Volt supply from Q117 (µPC14308) is used for other circuits. When the function switch is at MEM position, D4 (WZ050) supplies 5 Volts to the receiver, and D5 (WZ050) supplies 5 Volts to the transmitter.

Optional Tone Squelch Circuit

The Tone Squelch operation enables private communications on crowded channels by disabling the receiver's audio circuit until a preset tone signal is received. The transmitted signal is modulated by a tone signal within 70 Hz to 250 Hz, below the 300 Hz to 3000 Hz voice frequency range used in radio communications.

The tone signal is generated by Q502 (NE567), with its frequency set by R516, VR502, and C516. The tone signal level is set by VR504 and fed through buffer amplifier Q503 (2SK19GR) to a low-pass filter (unit "d" of operational amplifier Q501, MC3403). The tone signal is then superimposed on the speech signal by Q202. Preset frequency constants are obtained from the chart below:

The audio output from the receiver discriminator feeds unit "a" of Q501 (MC3403), which forms a high-pass filter. Unit "b" of Q501 forms a T-notch filter. Both filters remove the tone signal from the audio signal, which then feeds audio amplifier Q505 (2SC372Y) to receiver audio amplifier Q111. The tone signal passes through a low pass filter (unit "c" of Q501) and feeds Q502 (NE567). When the tone signal matches the preset transmitting frequency, pin 8 of Q502 goes low, causing Q504 (2SC372Y) to turn "OFF." This applies proper bias voltage to Q116 for normal operation. Without a proper tone signal, Q504 conducts, removing bias from Q116 and disabling the audio circuit. The conventional carrier squelch circuit remains operative when tone squelch is switched in, and the busy lamp lights up when any carrier is received.

Maintenance & Alignment

General

The FT-227R transceiver has been carefully aligned and tested at the factory. The solid-state devices ensure years of trouble-free service with normal, routine maintenance. The following precautions should be observed to prevent damage:

1. Do not exceed 14 Volts DC at the POWER receptacle. When operating mobile, check battery voltage under load (transmitter "keyed" in FM mode) with the engine running fast enough for the ammeter to show a "change." Do not operate the FT-227R if supply voltage is below 12 Volts DC.
2. Avoid direct exposure to sunshine or water.

Internal Layout Overview:

The internal layout of the FT-227R shows the Main Unit, divided into Transmitter and Receiver sections. The Display Unit, Channel Selector, and Photo Interrupter Unit are located at the top. The PLL Local Section, Modulator Converter Section, Tone Squelch Unit (if installed), Tone Burst Section, PLL Control Unit, and VCO Section are also identifiable. A red wire must be cut when the Tone Squelch Unit is installed.

Routine Maintenance

Routine maintenance involves keeping the transceiver clean and periodically checking transmitter RF power output and receiver sensitivity.

Cleaning:

When used in dusty or sandy areas, the interior should be periodically cleaned with a vacuum cleaner. Caked or accumulated dirt can be removed with a soft brush. Ensure the interior is thoroughly dry before reassembling. Wipe the exterior with a damp cloth.

Performance Checks

Perform all checks at 13.5 Volts DC (under load).

Check the transmitter output:

1. Connect a suitable 50 ohm dummy load/RF wattmeter to the ANT receptacle.
2. Set the channel selector to any channel and key the transmitter. The power output should be approximately 10 Watts, and the S-meter should read between 6 and 8 relative power output.

Check the receiver sensitivity:

1. Connect an AC VTVM to the SP receptacle, and set the SQUELCH control fully counter-clockwise.
2. Connect the RF output of a precision VHF signal generator to the ANT receptacle. Note the VTVM reading with no signal input. Adjust the VOLUME control and VTVM range for an approximate full scale reading (do not change VOLUME control setting after this).
3. Set the signal generator to the receiving frequency and adjust output amplitude until the VTVM reads 20dB (1/10th voltage) lower than the reading in step (b). This signal generator output voltage is the 20 dB quieting sensitivity, approximately 0.3 µV.

If performance checks indicate a need for realignment, it is recommended that the transceiver be returned to the dealer. Alignment procedures require special test equipment and techniques not normally available to the average owner. Attempts to realign tuned circuits without proper equipment may degrade performance.

Alignment

Some alignment procedures require special test equipment and techniques and should only be done by an expert technician.

Transmitter Alignment

RF Power Amplifier

1. Set the channel to 147.0 MHz. Connect a YP-150 50 ohm dummy load/watt meter to the antenna connector. Connect a VTVM between TP1 and ground (1V DC range).
2. Key the transmitter and peak T201 for maximum VTVM reading.
3. Set the HI/LOW switch to HIGH position and VR205 to extreme CCW position. Peak TC201 through TC206 for maximum power output as indicated on the YP-150.
4. Set the HI/LOW switch to LOW position and set VR206 for 1 Watt output.

AFP (Automatic Final Protection)

1. Connect the YP-150 to the antenna connector. Set VR205 to the extreme CCW position. Connect the VTVM to cathode (+) of D208 and ground (-) and adjust VR204 for minimum VTVM reading.
2. Slowly advance VR205 in CW (Clockwise) direction until the output power is about to decrease.

PO Meter

Set VR203 to the point where the S meter shows 8 with full output.

Deviation

1. Connect YP-150 to the antenna connector, the output of an audio oscillator between pin 2 (hot) and 1 (ground) of the microphone receptacle, and a deviation meter. Set the audio output level to 25 mV at 1 kHz.
2. Connect a frequency counter between TP3 of the PLL unit and ground.
3. Key the transmitter by grounding pin 3 of the microphone receptacle. Adjust T401 for a 10.7 MHz counter reading.
4. Set the output level of the audio signal generator to 25 mV at 1 KHz and adjust VR202 for ±5 kHz deviation.
5. Set the audio level to 1.5 mV. Adjust VR201 for a deviation of -2.5 kHz.

Tone Burst

1. Connect a YP-150 dummy load to the antenna connector and disconnect the microphone to prevent accidental voice modulation.
2. Temporarily connect pin 5 of Q215 to pin 14.
3. Connect a YC-500 frequency counter to the emitter of Q216, and set the TONE BURST switch to the ON position.
4. Key the transmitter and adjust VR207 to the desired burst frequency.
5. Connect a VTVM to the MIC IN terminal and adjust VR209 for 2.5 mV VTVM reading.
6. Remove the temporarily connected wire from step (b). Key the transmitter and adjust VR208 for desired burst duration.

Receiver Alignment

RF Amplifier

1. Connect the calibrated signal generator to the antenna connector and set the channel selector to 147.0 MHz.
2. Tune the signal generator to the receive frequency and peak L101 through L104 and TC101 through TC104 for maximum S meter reading.

First IF Amplifier

1. Connect a sweep generator to the second gate of Q102. Connect an oscilloscope through a detector to the drain of Q103.
2. Set the frequency of the sweep generator to 10.7 MHz and apply its output. Adjust T101 until the scope pattern (a bell-shaped curve centered at 10.7 MHz) is available.
3. Disconnect the sweep generator and scope. Measure the RF injection voltage to the second gate of Q103. A nominal value is 0.8-1.0 Volt rms.

S Meter Sensitivity

1. Apply the signal generator output to the antenna connector. Peak T102 for maximum S meter reading.
2. Set the output level of the signal generator to 20dB and adjust VR101 for full scale indication on the S meter.

Noise Squelch Threshold

1. Receive 0 dB signal from the signal generator.
2. Set the SQL control on the front panel to fully counter-clockwise position and slightly advance clockwise direction to minimum SQL position. Set VR102 to the point where the squelch starts to open.

PLL Circuit Alignment

1. Set the channel frequency to 146.00 MHz.
2. Connect the YC500S frequency counter to TP1 of the PLL unit and adjust TC309 for 5.1200 MHz, ensuring the RF voltage of the emitter of Q312 is approximately 1.6 Volts rms.
3. Connect an RF probe of the VTVM to the base of Q311 and peak TC308 for maximum VTVM reading. Slowly rotate TC308 in the direction of increasing capacitance until the VTVM reading becomes 5% lower than peak indication (approx. 60 mV rms).
4. Connect an RF probe of the VTVM to the base of Q305. Key the transmitter and peak T302 for maximum VTVM reading (approx. 170 mV rms).
5. Connect the YC-500S frequency counter between the cathode of D302 in the PLL unit and ground. Set the FUNCTION switch to SIMP. Adjust TC302 for 135.300 MHz counter reading.
6. Set the FUNCTION switch to -600. Key the transmitter and adjust TC303 for 134.700 MHz counter reading. Adjust TC304 for 135.900 MHz at +600.
7. Set the FUNCTION switch to SIMP. Press the 5UP switch down. Adjust TC305 for 135.305 MHz in receive mode. Key the transmitter at -600 and adjust TC306 for 134.705 MHz, at +600 kHz adjust TC307 for 135.905 MHz.
8. Connect a VTVM (DC10V range) between the cathode of D324 and ground. Adjust TC301 for 3.4 Volt VTVM reading.
9. Connect an RF probe of the VTVM between the TX out terminal and ground in the PLL unit. Peak T402-T408 for maximum VTVM reading in transmit.

Optional Tone Squelch Alignment

The optional tone squelch unit is factory set to 77 Hz operation. The tone squelch frequency can be chosen to any frequency between 70 Hz to 160 Hz by adjusting VR502. The transmitting level of the tone signal is set by VR504.

Parts List Summary

This section provides a comprehensive list of components used in the FT-227R transceiver, categorized by unit and component type. It includes:

• Main Chassis Components: Transistors (e.g., 2SD235, 2SC372Y, 2SA4960), Diodes (e.g., 1S1555, Zener Diodes), Resistors (Carbon Film), Potentiometers, Capacitors (Ceramic, Electrolytic), Inductors (Lowpass Coil, AF Choke Coil), Crystals (HC-18/U), Meters, Speakers, Switches, Connectors, and Pilot Lamps.
• PLL Unit Components: ICs (e.g., TC5081P, uPD857C), FETs (e.g., 2SK19GR), Transistors (e.g., 2SC372Y, 2SC373), Diodes (e.g., 1S1555, Varactor Diodes), Crystals, Resistors, Capacitors (Ceramic, Mylar Film, Tantalum, Electrolytic), Trimmer Capacitors, Inductors, and Transformers.
• Display Unit Components: ICs (e.g., MC14305, MSM561), Transistors (e.g., 2SC372Y), Diodes (LEDs), Resistors, Capacitors (Ceramic, Tantalum, Electrolytic), and Heat Sinks.
• PLL Control Unit Components: MOS ICs (e.g., MC14519B, MC14042B), Transistors (e.g., 2SC735Y), Diodes (Silicon Diode), and Resistors.
• Photo Interrupter Board Components: Photo Interrupters (PS4001) and Resistors.
• Tone Squelch Unit Components: ICs (e.g., MC3403, NE567), FETs (e.g., 2SK19CR), Transistors (e.g., 2SC372Y), Diodes (Zener Diode), Resistors, Potentiometers, and Capacitors (Mylar, Electrolytic, Tantalum).

Each component is listed with its symbol number, part number, description, and relevant specifications (e.g., voltage, capacitance, resistance, type).

Transistor & IC Connections

This section provides diagrams illustrating the pin configurations and terminal connections for various transistors and integrated circuits used in the FT-227R. These diagrams are essential for maintenance and repair, showing the source, drain, gate, collector, emitter, base, and specific pin assignments for each component. Examples include: 2SK19Y, 2SK19GR, 3SK40M, 3SK51, PS4001, 2SC535A, 2SA564A, 2SA733, 2SC2053, 2SC710D, MPSA13, 2SC730, 2SD235, 2SA496O, MRF212 transistors, and µPC14305, µPC14308, µPC577H, TC5081, µPC575C2, MC14011B, MC14081B, MSM561, MC14049B, MC14008B, MC14510B, µPD857C, MC14028B, MC14511B, MC14042B, MC14519B integrated circuits. Each diagram clearly labels the pins and their functions, such as input, output, ground, and specific gate/collector/emitter connections.

Q308 (µPD857C) Programmable Divider Code

This table details the programmable divider code for the Q308 (µPD857C) IC, showing the relationship between operating frequency, dial display, and the corresponding programmable divider ratio (P0-P11 values). This information is crucial for understanding the frequency synthesis within the PLL unit.

Note: ※1 HIGH LEVEL (5V), ※0 LOW LEVEL (0V)