Kenwood TW-4000A 2 m - 70 cm FM DUAL BANDER Instruction Manual

Introduction

Welcome to the ownership of the Kenwood TW-4000A transceiver. This manual provides detailed instructions for operation. The unit is engineered to high standards for dependable performance.

1. FEATURES

• Compact Dual Band Transceiver: Combines 2 m and 70 cm band transceivers in a compact housing for improved operation, economy, and design.
• Large LCD Display: Ensures good visibility of operation and control conditions.
• Front Layout for Simple Operation: Easy-to-use display and keyboard for straightforward operation of both bands.
• Newly Developed Microcomputer: Offers multi-functionality in a compact unit.
• Use of Hybridized ICs: Achieves high performance and high density through hybridized circuits.
• Use of Diecast Frame: Features a durable diecast aluminum frame.
• Memory Back-up Lithium Battery: Provides approximately 3 years of memory backup.
• Synthesized Voice System (Optional): With the VS-1 option, the unit can announce operation conditions, allowing verification without looking at the display.

2. CONTROLS AND THEIR FUNCTIONS

Front Panel Controls:

• VOL (Volume)/Power Switch: Controls audio volume and powers the unit ON/OFF.
• SQL (Squelch) Control: Adjusts the squelch threshold to eliminate background noise.
• Microphone Connector (8 Pins): For connecting the microphone.
• HI/LO Switch: Selects high (25W) or low (approx. 5W) RF output power.
• D.LOCK (Dial Lock): Locks the tuning dial to prevent accidental frequency changes.
• TONE: Activates the repeater control tone signal (1,750 Hz) circuit and sets the unit to transmit mode.
• F.S (Frequency Step) Switch: Alternates frequency step between 25 kHz and 5 kHz. The F.S indicator lights when 5 kHz step is selected.
• DIM (Dimmer) Switch: Selects bright or dim intensity for the display and illumination.
• TUNING DIAL: Rotates clockwise to increase frequency and counterclockwise to decrease frequency. One click changes the frequency by one step.

Display Panel and Indicators:

• BUSY Indicator: Lights when the squelch is open in receive mode, indicating an active channel.
• ON AIR Indicator: Lights during transmission.
• F.S Indicator: Lights when the frequency step is set to 5 kHz.
• PR.W Indicator: Lights when the PR.W switch is ON.
• COM Indicator: Indicates '8' or '9' when the COM-8 or COM-9 switch is ON, respectively.
• Band Indicator: Shows '14' for the 2 m band and '43' for the 70 cm band.
• Scan Indicator (Dot): Flashes during scan operation.
• Frequency Display: Shows the current operating frequency, accurate to the 1 kHz digit.
• VFO A/B Indicator: Lights when VFO A or VFO B is operating.
• S/RF Level Indicator: Displays received signal strength or transmit RF output power.
• MR Indicator: Lights when the MR key is ON, indicating the selected memory channel.
• Memory Channel Indicator: Lights up on a specified memory channel.
• MS Indicator: Lights during memory scan operation.
• OFFSET Indicator: 'S' indicates Simplex (transmit and receive frequencies are the same). 'D-A' indicates transmit frequency is shifted -600 kHz (2m) or -7.6 MHz (70cm). 'D-B' indicates transmit frequency is shifted +600 kHz (2m) or -1.6 MHz (70cm).

Keyboard Functions:

• A/B Key: Selects between VFO A and VFO B.
• SCAN Key: Initiates scan operation. Resumes scan from a BUSY stop.
• MR Key (Memory Recall): Recalls the specified memory channel.
• DWN/UP Key: In VFO operation, shifts frequency by 1 MHz steps. In MR operation, shifts memory channels. During scan, controls scan direction.
• 8-COM-9 Key: Recalls memory channel 8 (145.000 MHz) or 9 (433.000 MHz). These channels have priority and can be programmed.
• V-MS-U Key: Selects band (VHF or UHF) and initiates scan. MS-V scans 2m band, MS-U scans 70cm band.
• REV/OFFSET Key:
  • OFFSET: Sets transmit frequency offset for repeater operation (e.g., ±600 kHz). Cycles through S (Simplex), D-A, D-B.
  • REV: Reverses receive and transmit frequencies to check repeater input frequency.
• M.CH Key: Selects the next higher memory channel. Holding the key selects channels sequentially.
• PR.W Key (Priority Channel Watch): Monitors memory channel 1 (priority channel) at intervals. The PR.W indicator lights when active.
• M Key (Memory Input): Stores the current frequency and offset settings into memory channels.

3. INSTALLATION AND CONNECTION

Antenna Connection:

• The transceiver has two antenna connectors: VHF ANT (M type) and UHF ANT (N type), both 50 ohms impedance.
• For optimal performance, use a suitable antenna and adjust for low VSWR (preferably less than 1.5).
• Individual Antennas: Connect separate 2 m and 70 cm antennas to their respective connectors. Use the supplied Antenna ID stickers to prevent reversed hook-up.
• Common Antenna: A common antenna can be used with a duplexer to connect both bands to a single antenna. The optional MA-4000 is available. Ensure the duplexer is correctly installed.

Interconnection and Mounting:

• External Speaker: Connect an optional SP-40 external speaker to the SP terminal for clearer audio.
• Mobile Installation: Use the supplied mounting kit to secure the transceiver under the dashboard or console. Ensure adequate ventilation and keep away from electronic control equipment if possible.
• Coaxial Cable: Use low-loss coaxial cable, especially for longer runs (10m or more), such as RGB/U.
• Power Supply: Connect the supplied DC power cord directly to the vehicle's battery terminals (13.8V DC). Avoid using the cigarette lighter socket due to potential poor connections and voltage drops. Ensure correct polarity (red for positive, black for negative).
• Ignition Noise: If ignition noise is present, consider using suppressor spark plugs or the Kenwood PG-3A noise suppressor.

Fixed Station Installation:

• Power Supply: A regulated DC power supply (13.8V DC, 8A or more) is required. The Kenwood PS-430 is recommended. Avoid using battery charging power supplies.
• Antenna: Select a fixed station antenna (e.g., ground plane or Yagi) with an SWR of less than 1.5 for optimal performance and to prevent transceiver protection activation.

4. OPERATION

Initial Setup:

1. Connect antenna and power.
2. Depress the VOL control to turn on the transceiver. Indicators on the display will illuminate.
3. Adjust VOL clockwise to hear noise or a QSO.
4. Use the SQL control to eliminate no-signal noise by slowly turning it clockwise until the noise disappears and the BUSY indicator turns off.
5. Tune to the desired frequency using the tuning dial and UP/DWN keys.
6. Recall COM channels (CH 8: 145.000 MHz, CH 9: 433.000 MHz) by pressing the respective keys.

SQL (Squelch) Control Operation:

To eliminate receiver noise when no signal is present, slowly adjust the squelch control clockwise until the noise disappears and the BUSY indicator is off. The squelch opens (BUSY indicator lights) when a signal is received. This control also aids in scan operation. Readjust as needed for consistent reception, especially during mobile operation.

PR.W (Priority Channel Watch) Operation:

Press the PR.W key to monitor memory channel 1. The transceiver checks CH 1 for approximately one second every ten seconds. The PR.W indicator lights when active. Reception is interrupted if transmitting during CH 1 monitoring. The function can be turned ON/OFF by pressing the PR.W key.

Transmitter Operation:

• Ensure the antenna impedance is 50 ohms.
• Check the intended transmit frequency for busy status before transmitting.
• Depress the microphone PTT switch to transmit. The ON AIR indicator will light, and the LCD bar meter shows transmitter power. Maintain a talk distance of approximately 5 cm from the microphone.
• HI/LO Power Switch: Use the HI/LO switch to reduce RF output power from 25W to approximately 5W for local communication, reducing interference and power consumption. The power indication on the meter will drop accordingly.

Memory Input Operation:

Use memory channels to store frequencies and TX OFFSET settings. Initial settings include CH 1 (Vacant), CH 2-7 (Vacant), CH 8 (145.000 MHz), CH 9 (433.000 MHz), and CH 0 (Dual memories).

Memory Input Procedure:

1. Memory Channel Setting: Use the M.CH key to select the desired memory channel.
2. Frequency Setting: Set the frequency to be stored in VFO mode.
3. TX OFFSET Setting: Use the OFFSET key to select the desired offset (S, D-A, D-B).
4. Memory Input: Depress the M key to store the frequency and offset settings. A beep will confirm storage.

Memory Input in CH 0:

To store transmit and receive frequencies separately in CH 0, follow the memory input procedure, then set the transmit frequency, depress the PTT switch to enter transmit mode, and while transmitting, depress the M key.

Memory Recall (MR):

Select a memory channel using the M.CH key, then press the MR key to recall the stored frequency. If a memory channel is empty, only the channel number is displayed.

Scan Operation:

Before scanning, set the SQL control to eliminate noise. The transceiver supports VFO scan, MR scan, COM scan, and MS scan (VHF/UHF memory scan).

• VFO Scan: Operates within a 1 MHz range in 25 kHz steps (or 5 kHz if F.S indicator is lit).
• MR Scan: Scans memory channels until the MR key or PTT switch is pressed.
• COM Scan: Scans COM channels 8 and 9 alternately every 5 seconds.
• MS Scan: Scans 2 m band memory channels only.

Scan direction can be controlled using the UP/DWN keys or microphone switches. Scan hold after a signal stops is approximately one second. Empty and skipped channels are bypassed during MR and MS scans.

Scan Lockout (Skip) Operation:

Depress the M key during MR operation to skip the displayed memory channel during scans. The scan indicator (dot) will go off. Depressing the M key again releases the lockout.

TX OFFSET Operation:

The OFFSET indicator shows frequency shifts for repeater use: 'D-A' for a negative offset, 'D-B' for a positive offset. 'S' indicates Simplex (no offset). If the transmit frequency exceeds band limits due to offset settings, the transceiver automatically switches to Simplex mode.

Microphone Operation:

• Remote Control (UP-DWN): Use the UP/DWN switches on the microphone to change frequency (VFO) or memory channel (MR). During scan, they control scan direction and rapid scan.
• Voice Synthesizer Operation: The optional VS-1 unit provides voice announcements for operating status. The V.RCL switch on the front panel or microphone activates voice confirmation.
• Microphone Switches: The MR and BAND switches on the microphone control memory channel and band selection, respectively, when held down with the UP/DWN switches. The microphone MR switch has priority over transceiver keys.

5. ACCESSORIES

• VS-1 (Voice Synthesizer Unit): Provides voice output for operation status, language selection (English/Japanese), and talk speed adjustment.
• MA-4000 VHF/UHF Dual Band Mobile Antenna: A mobile antenna with a built-in duplexer for dual band operation.
• PS-430 Fixed Station DC Power Supply: Recommended power supply for fixed station use.
• SP-40 Mobile Speaker: Provides clear audio output, designed for mobile environments.

6. ADDITIONAL INFORMATION

• General Information: The transceiver is factory aligned. For service, contact an authorized dealer. Internal adjustments should only be made by qualified technicians.
• TX Final Module Protection: The transceiver protects the final module by reducing drive power when reflected power (high SWR) is detected.
• Battery Precaution: Disconnect the power cable from the transceiver when charging or jump-starting a vehicle battery.
• Ordering Spare Parts: When ordering parts, specify model number, serial number, schematic number, PCB number, part number, and name.
• Service: Pack the unit in its original box for repair and include a detailed description of the problem and contact information.

7. BLOCK DIAGRAM

A block diagram illustrating the internal circuitry of the TW-4000A is provided for technical reference.

8. SPECIFICATIONS

General:

• Semiconductors: MPU 1, ICs 18, Transistors 44, FETs 12, Diodes 62.
• Frequency Range: VHF 144.0-146.0 MHz, UHF 430.0-440.0 MHz.
• Mode: FM (F3).
• Antenna Impedance: 50 ohms (VHF & UHF).
• Power Requirement: 13.8 V DC ±15%.
• Grounding: Negative.
• Operating Temperature: -20°C to +50°C.
• External Speaker Impedance: 8 ohms.
• Current Drain: 0.6 A (receive), Max. 7.5 A (HI transmit), 3.3 A (LOW transmit), 2 μA (backup).
• Dimensions: 161 mm (W) x 60 mm (H) x 217 mm (D).
• Weight: 2.0 kg (4.18 lbs).

Transmitter:

• RF Output Power: HI 25 Watts min. (2m/70cm), Low 5 Watts approx. (adjustable up to 10W).
• Modulation: Reactance.
• Frequency Tolerance: Less than ±15 x 10⁻⁴ (-10°C to +50°C).
• Spurious Radiation: Less than -60 dB.
• Maximum Frequency Deviation: ±5 kHz.
• Audio Distortion: 3% max.

Receiver:

• Circuitry: Double superheterodyne.
• Intermediate Frequency: 1st 30.865 MHz, 2nd 455 kHz.
• Sensitivity: SINAD 12 dB < 0.17 μV; S+N/N > 50 dB at 1 mV input.
• Selectivity: > 14 kHz (-6 dB), < 28 kHz (-60 dB).
• Spurious Response: Better than 70 dB.
• Squelch Sensitivity: < 0.1 μV (threshold).
• Auto Scan Stop Level: < 0.16 μV (threshold).
• Audio Output: > 2.0 watts across 8 ohms (10% dist.).

Microphone Supplied:

• Semiconductors: Diodes 4.
• Impedance: 500 ohms.