Kenwood MC-48 - User Manual

KENWOOD
AUTOPATCH MICROPHONE IMvI G = 2}. Ss
INSTRUCTION MANUAL
INTRODUCTION
The MODEL MC-48 is an AUTOPATCH MICRO-
PHONE specifically designed to be used with KEN-
WOOD TRANSCEIVER models TW-4000A, TM-
201A and TM-401A. It features a 16 key AUTO-
PATCH encoder and frequency UP and DOWN
switches.
FEATURES:
1. Microphone is equipped with a tone-pad en-
coder.
2. A built-in delay holds the microphone (and
transceiver) in transmit mode for about 0.7
second between key presses.
Se)
. Micro switch is used for PTT.
4. Specifically designed for transceiver operation to
provide good sensitivity and frequency response
and clear tones.
APPLICABLE MODEL
TW-4000A
TM-201A, TM-401A
SPECIFICATIONS
[GENERAL]
Power requirement
Current drain:
Connector:
Dimensions:
Weight:
[MICROPHONE]
Element:
Sensitivity:
impedance:
[AUTOPATCH]
Key:
Tone output
8.5 VDC + 10%
Less than 20mA (at 8.5
V DC)
8 pins
W 51xH 73x D 33 mm
145 gr. (Approx.)
Electret condensor
—70dB (OdB=1V/1iu
bar)
9002.
16 keys
3.8mV/5.6KQ
(Adjustable)
(With the keys 3 and 6
simultaneously depressed)
G) 8C (+8 V) (4) UP
(3) DWN
© NC
(2) STBY (PTT)
(4) MIC
(8) GND
FRONT VIEW
OPERATION:
16 Key AUTOPATCH encoder
When the tone encoder is started operating, the
transceiver is set in transmit mode even with the
PTT switch released.
Frequency UP/DOWN switches
These switches are used to step the operating fre-
quency up or down.
When the UP or DOWN switch is held depressed,
the frequency shifts rapidly.
PTT switch
Simply press the PTT switch to activate the trans-
mitter.

Summary

Introduction to the Kenwood MC-48 Autopatch Microphone

Key Features of the MC-48 Microphone

Applicable Models for MC-48 Microphone

Specifications of the MC-48 Microphone

General Specifications

Details general specifications including power, current, connector, dimensions, and weight of the MC-48 microphone.

Microphone Specifications

Covers microphone-specific details such as element type, sensitivity, and impedance.

Autopatch Specifications

Outlines specifications related to the autopatch function, including key count and tone output.

Operation of the MC-48 Microphone

16 Key Autopatch Encoder Operation

Explains the function of the 16-key autopatch encoder, including transmit mode activation.

Frequency UP;DOWN Switches

Details how the UP/DOWN switches are used to change operating frequency.

PTT Switch Operation

Describes the function of the PTT switch for activating the transmitter.

Schematic Diagram of MC-48 Microphone

Frequency Response Graph

Overview

1. Function Description
2. Important Technical Specifications
3. Usage Features
4. Maintenance Features

The Kenwood MC-48 Autopatch Microphone is a specialized accessory designed for use with Kenwood transceiver models TW-4000A, TM-201A, and TM-401A. Its primary function is to provide an integrated solution for tone-pad encoding, frequency control, and push-to-talk (PTT) operation, enhancing the functionality of the compatible transceivers.

Function Description

The MC-48 serves as a comprehensive control interface for radio communication. It incorporates a 16-key autopatch encoder, allowing users to generate DTMF (Dual-Tone Multi-Frequency) tones for various applications, such as accessing telephone autopatch systems or controlling remote devices. The microphone also features dedicated UP and DOWN switches for convenient frequency adjustment of the connected transceiver. A built-in delay mechanism ensures that the microphone and transceiver remain in transmit mode for approximately 0.7 seconds between successive key presses, preventing premature disengagement during rapid tone generation. The PTT function is managed by a micro switch, providing a tactile and reliable means to activate the transceiver's transmitter. The microphone is specifically engineered to deliver high sensitivity, a broad frequency response, and clear tone generation, ensuring optimal audio quality and reliable operation.

Important Technical Specifications

• Power Requirement: The MC-48 operates on 8.5 V DC ± 10%.
• Current Drain: It draws less than 20mA at 8.5 V DC, indicating low power consumption.
• Connector: The microphone utilizes an 8-pin connector for interfacing with compatible transceivers.
• Dimensions: The physical dimensions of the microphone are W 51 mm x H 73 mm x D 33 mm.
• Weight: The device weighs approximately 145 grams, making it lightweight and portable.
• Microphone Element: It employs an electret condenser element, known for its sensitivity and clarity.
• Microphone Sensitivity: The sensitivity is rated at -70 dB (0 dB = 1 V/1 µbar).
• Microphone Impedance: The microphone has an impedance of 900Ω.
• Autopatch Keys: It features 16 keys for tone generation.
• Tone Output: The tone output is 3.8mV/5.6KΩ (adjustable). This output is measured when keys 3 and 6 are simultaneously depressed, indicating a specific test condition for tone level.
• IC: The integrated circuit used is an LR4087.
• Ceramic Resonator: It includes an L78-0003-05 ceramic resonator.

Usage Features

• 16 Key Autopatch Encoder: This feature allows users to generate DTMF tones. When the tone encoder is activated, the transceiver automatically enters transmit mode, even if the PTT switch is not pressed, facilitating hands-free tone generation.
• Frequency UP/DOWN Switches: These dedicated switches enable users to incrementally adjust the operating frequency of the transceiver. Holding either the UP or DOWN switch depressed causes the frequency to shift rapidly, providing quick navigation across the frequency band.
• PTT Switch: A simple press of the PTT switch activates the transceiver's transmitter, allowing for voice communication. The micro switch design ensures a reliable and responsive PTT function.
• Built-in Delay: The 0.7-second delay between key presses in transmit mode is a crucial feature for autopatch operations, preventing accidental disengagement of the transmit function during rapid tone sequences.
• Optimized Audio Performance: The microphone's design is tailored for transceiver operation, providing good sensitivity, a wide frequency response, and clear tones, which are essential for effective communication and tone-based control.

Maintenance Features

The manual does not explicitly detail maintenance features in a dedicated section. However, the provided schematic diagram and parts list offer insights into the internal components, which would be essential for any repair or maintenance activities. The availability of a detailed parts list, including specific part numbers for components like the IC (LR4087), ceramic resonator (L78-0003-05), microphone element (T97-1024-08), and various switches, suggests that component-level repair might be feasible. The schematic diagram provides a comprehensive view of the circuit, which is invaluable for troubleshooting and diagnosing issues. The robust construction, indicated by the specified dimensions and weight, suggests a durable device that would likely require minimal routine maintenance beyond general cleaning. The focus on "clear tones" and "good sensitivity" implies that maintaining the integrity of the microphone element and associated circuitry would be key to preserving its performance.

Kenwood MC-48 Specifications