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INSTRUCTION MANUAL 144 MHz FM TRANSCEIVER TM-281A 430 MHz FM TRANSCEIVER TM-481A...
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The market code is printed on the barcode label of the transceiver is no exception. As you learn how to use this carton box. transceiver, you will find that Kenwood is pursuing “user Refer to the product specifications {pages 69, 70} for friendliness”. For example, each time you change the information on the available operating frequencies within Menu No.
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• If an abnormal odor or smoke is detected coming from the transceiver, turn OFF the power immediately. Contact a Kenwood service station or your dealer. • This transceiver is designed for a 13.8 V power source.
CONTENTS SUPPLIED ACCESSORIES ........1 VFO M ............15 MHz M ............16 WRITING CONVENTIONS FOLLOWED IN THIS MANUAL ............1 ........16 IRECT REQUENCY NTRY CHAPTER PREPARATION CHAPTER MENU SETUP MOBILE INSTALLATION .......... 2 WHAT IS A MENU? ..........18 MENU ACCESS ............
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CTCSS F ......45 ........30 ELECTING A REQUENCY SING THE UNING ONTROL CTCSS F ID S ........ 45 ......31 REQUENCY SING THE ICROPHONE EYPAD DCS ................. 46 CLEARING A MEMORY CHANNEL ....... 31 DCS C ........46 NAMING A MEMORY CHANNEL ......32 ELECTING A DCS C ID S...
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LOCK FUNCTION ........... 56 TUNE ENABLE ............56 MICROPHONE PF KEYS (K ) ..57 EYPAD ODELS NARROW BAND FM OPERATION ......58 POWER-ON MESSAGE ......... 58 PROGRAMMABLE VFO ......... 59 TIME-OUT TIMER ........... 60 CHAPTER MICROPHONE CONTROL MIC LOCK ............... 62 CHAPTER OPTIONAL ACCESSORIES CHAPTER...
SUPPLIED ACCESSORIES WRITING CONVENTIONS FOLLOWED IN THIS MANUAL After carefully unpacking the transceiver, identify the The writing conventions described below have been items listed in the table below. We recommend you keep followed to simplify instructions and avoid unnecessary the box and packaging for shipping. repetition.
PREPARATION 2 Position the transceiver, then insert and tighten MOBILE INSTALLATION the supplied hexagon SEMS screws (4) and flat To install the transceiver, select a safe, convenient washers (4). location inside your vehicle that minimizes danger to your • Double check that all hardware is tightened to prevent passengers and yourself while the vehicle is in motion.
4 Confirm the correct polarity of the connections, then DC POWER CABLE CONNECTION attach the power cable to the battery terminals; red connects to the positive (+) terminal and black connects to the negative (–) terminal. Locate the power input connector as close to the transceiver as •...
2 Connect the transceiver’s DC power connector to the IXED TATION PERATION connector on the DC power cable. In order to use this transceiver for fixed station operation, • Press the connectors firmly together until the locking tab you will need a separate 13.8 V DC power supply (not clicks.
If newly installed fuses continue to blow, disconnect the type of antenna and its correct installation. The the power cable and contact your authorized Kenwood transceiver can give excellent results if the antenna dealer or an authorized Kenwood service center for system and its installation are given careful attention.
ACCESSORY CONNECTIONS ICROPHONE For voice communications, connect a 600 Ω microphone XTERNAL PEAKER equipped with an 8-pin modular plug into the modular socket on the front of the main unit. Press firmly on the If you plan to use an external speaker, choose a speaker plug until the locking tab clicks.
To utilize the optional MCP-1A software, you must first connect the transceiver to your PC using an optional Programming Cable (via the microphone jack). The MCP-1A is free downloadable software available from Kenwood at the following URL: http://www.kenwood.com/i/products/info/amateur/software_download.html Note: Ask your dealer about purchasing a Programming Cable.
YOUR FIRST QSO 1 Press [ ] (Power) briefly to switch the transceiver power ON. Are you ready to give your transceiver a quick try? Reading this section should get your voice on the • A high pitched double beep sounds and a Power-on message appears momentarily.
GETTING ACQUAINTED Press [F] then press [MENU] to enter Menu Mode FRONT PANEL {page 18}. Note: This section describes only the main functions of the front Turn to select: panel controls. Explanations for functions not described here are provided in the appropriate sections of this instruction manual. •...
In MR Mode, press [F] then press [VFO] to transfer DISPLAY the contents of the selected Memory Channel to the VFO {page 33}. t MR key Press to enter Memory Recall Mode {page 30}. In this mode, you can change memory channels using the Tuning control or Mic [UP]/[DWN].
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Appears when the Automatic Simplex Check (ASC) Appears when the Memory Channel Lockout function is function is activated {page 26}. ON {page 42}. Appears when the Priority Scan function is activated Shows the strength of transmitted {page 15} and received {page 42}.
REAR PANEL MICROPHONE DTMF Microphone Microphone (KMC-30) q Antenna connector q PTT (Push-to-Talk) switch Connect an external antenna {page 5} here. When Press and hold to transmit. Release to receive. making test transmissions, connect a dummy load in place of the antenna. The antenna system or load w DWN/ should have an impedance of 50 Ω.
r CALL/A key EYPAD IRECT NTRY Identical to the front panel CALL key. This key can The microphone keypad (keypad models only) allows you be reprogrammed if desired {page 57}. Press and hold to make various entries depending on which mode the Mic [PTT], then press [CALL/A] to transmit A.
OPERATING BASICS SWITCHING THE POWER ON/OFF ADJUSTING THE SQUELCH 1 Press [ ] (Power) to switch the transceiver power The purpose of Squelch is to mute the speaker when no signals are present. With the squelch level correctly set, you will hear sound only while actually receiving signals. •...
2 Press [MENU] and turn the Tuning control to select “H” (high; default) or “L” (low) power. TRANSMITTING 3 Press [MENU] to store the setting or any other key to 1 To transmit, hold the microphone approximately 5 cm cancel. (2 inches) from your mouth, then press and hold Mic [PTT] and speak into the microphone in your normal 4 Press any key other than [MENU] to exit Menu Mode.
IRECT REQUENCY NTRY If the desired operating frequency is far away from the In addition to turning the Tuning control or pressing Mic current frequency, it is quicker to use the MHz Tuning [UP]/[DWN], there is another way to select the frequency. Mode.
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Note: If the entered frequency does not match the current frequency Example 1 step size, the frequency is automatically rounded down to the next To enter 145.750 MHz: available frequency. When the desired frequency cannot be entered exactly, confirm the frequency step size {page 54}. Key in Display [Enter]...
MENU SETUP 2 Turn the Tuning control to select your desired Menu. WHAT IS A MENU? • As you change the Menu No., a brief explanation of each Many functions on this transceiver are selected or menu appears along with its current parameter. configured via a software-controlled Menu rather than through the physical controls of the transceiver.
Page 2.5( )/5 / 6.25/ 10/ 12.5/ 15/ TM-281A Only TM-281A: 12.5 kHz Frequency step size 20/ 25/ 30/ 50/ 100 kHz TM-481A: 25 kHz Tone frequency 67.0 ~ 254.1 kHz 88.5 CTCSS frequency 67.0 ~ 254.1 kHz 88.5 DCS code...
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On the Menu Function Selections Default display Page Varies (see CALL key CALL/ 1750 25,35 reference page) 1750 Hz tone TX hold ON/ OFF Time-out Timer 3/ 5/ 10 min. Busy Channel Lockout ON/ OFF P.ON.MSG Power-on message 6 character −...
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On the Menu Function Selections Default display Page MONI/ ENTER/ 1750/ VFO/ MR/ CALL/ Microphone programmable MHZ/ REV/ SQL/ M--V/ M.IN/ C.IN/ function key MENU/ SHIFT/ LOW/ BRIGHT/ LOCK/ TONE/ STEP MONI/ ENTER/ 1750/ VFO/ MR/ CALL/ Microphone programmable MHZ/ REV/ SQL/ M--V/ M.IN/ C.IN/ function key MENU/ SHIFT/ LOW/ BRIGHT/ LOCK/ TONE/ STEP...
OPERATING THROUGH REPEATERS Repeaters, which are often installed and maintained OFFSET PROGRAMMING FLOW by radio clubs, are usually located on mountain tops Select a receive frequency. or other elevated locations. They generally operate at higher ERP (Effective Radiated Power) than a typical station.
PROGRAMMING AN OFFSET ELECTING AN FFSET REQUENCY You must first select an amateur radio repeater To access a repeater which requires an odd-split downlink frequency as described in “S frequency pair, change the offset frequency from the ELECTING AN FFSET ”.
4 Press any key other than [MENU] to exit Menu Mode. CTIVATING THE UNCTION To activate Tone, press [F], [CALL]. Available Tone Frequencies • As you press [F], [CALL], the selection cycles as follows: 42 Tone Frequencies (Hz) “OFF” ➞ “TONE” ➞ “CTCSS” ➞ “DCS” ➞ “OFF”. •...
AUTOMATIC REPEATER OFFSET TRANSMITTING A 1750 Hz TONE This function automatically selects an offset direction, Call Channel default settings: according to the frequency on the VHF band. The • On M market models, pressing [CALL] changes the transceiver is programmed for an offset direction as transceiver to the Call Channel {page 35}.
Note: REVERSE FUNCTION You can turn the Reverse function ON when you are operating in ◆ Simplex Mode. However, it does not change the Transmission/ The reverse function exchanges a separate reception Reception frequencies. and transmission frequency. So, while using a repeater, If pressing [REV] places the reception frequency outside the ◆...
Note: • To quit the function, press any key. Pressing [PTT] causes the “ ” icon to quit blinking. ◆ • When the tone frequency is identified, a beep sounds and ASC can be activated while operating in Simplex Mode. ◆...
MEMORY CHANNELS In Memory Channels, you can store frequencies and 4 Press [MENU] to accept or press any other key to related data that you frequently use so that you do not cancel. need to reprogram that data every time. You can quickly Note: recall a programmed channel through simple operation.
Note: The data listed below can be stored in each Memory Channel: ◆ Memory Channel Lockout cannot be set to the Program Scan Memory (L0/U0 ~ L2/U2) and Priority Channel (Pr). Simplex & Parameter Odd-Split Repeater STORING SIMPLEX FREQUENCIES OR STANDARD REPEATER FREQUENCIES 1 Press [VFO].
• Memory Channel numbers L0/U0 ~ L2/U2 {page 38}, Pr {page 41} are reserved for other functions. 5 Turn the Tuning control or press Mic [UP]/[DWN] to select the Memory Channel in which you want to store the data. 6 Press [MR] to store the data to the channel. Note: ◆...
CLEARING A MEMORY CHANNEL SING THE ICROPHONE EYPAD You can also recall a Memory Channel by entering a To erase an individual Memory Channel: desired Memory Channel number with the microphone 1 Recall the Memory Channel you want to erase. keypad.
5 Press [MR]. NAMING A MEMORY CHANNEL • The cursor moves to the next digit. You can name Memory Channels using up to 6 alphanumeric characters. When you recall a named Memory Channel, its name appears on the display in place of the stored frequency.
MEMORY CHANNEL TRANSFER HANNEL HANNEL RANSFER You can copy channel information from one Memory \ VFO T EMORY RANSFER Channel to another. This function is useful when storing frequencies and associated data that you temporarily After retrieving frequencies and associated data from change in Memory Recall Mode.
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The tables below illustrate how data is transferred ∆ Channel 01 ~ 199 L0/U0 L2/U2, Pr between Memory Channels. ∆ ∆ Channel 01 ~ 199 Channel 01 ~ 199 ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆...
Call Channel. The default Call Channel frequency is as follows; TM-281A: 144.000 MHz TM-481A: 440.000 MHz Note: Unlike Memory Channels 0 to 199, the Call Channel cannot be cleared. To also store a separate transmit frequency, continue with the following...
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While in Channel Display mode, you cannot activate the CHANNEL DISPLAY following functions: While in this mode, the transceiver displays only Memory • VFO Mode Channel numbers (or Memory Names if they have been stored), instead of frequencies. • VFO Scan 1 With the transceiver power OFF, press [REV]+[ •...
SCAN Scan is a useful function for hands-off monitoring of your Note: favorite frequencies. By becoming comfortable with all When the CTCSS or DCS function is activated, the transceiver ◆ stops at a busy frequency and decodes the CTCSS tone or DCS types of scan, you will increase your operating efficiency.
NORMAL SCAN ROGRAM When you are operating the transceiver in VFO Mode, You can limit the scanning frequency range. There are 3 types of scanning are available: Band Scan, Program 3 memory channel pairs (L0/U0 ~ L2/U2) available for Scan, and MHz Scan. specifying the start and end frequencies.
7 Turn the Tuning control or press Mic [UP]/[DWN] to select a matching Memory Channel from U0 ~ U2. MHz Scan allows you to scan an entire 1 MHz frequency • For example, if you have selected “L0” in step 3, range within the current VFO frequency.
1 Press [MR] and turn the Tuning control or press Mic MEMORY SCAN [UP]/[DWN] to select a Memory Channel in the range Memory Scan monitors Memory Channels in which you of the group you want to scan. have stored frequencies. 2 Press [MENU] (1s).
CALL SCAN PRIORITY SCAN You can alternate between monitoring the Call Channel You may sometimes want to check your favorite and the current operating frequency. frequency activities while monitoring other frequencies. In this case, use the Priority Scan function. Priority Scan 1 Select the frequency (in VFO or Memory Recall Mode) checks the activities of the Priority Channel every you want to monitor.
MEMORY CHANNEL LOCKOUT SING RIORITY 1 Press [F], [MENU] and turn the Tuning control to You can lock out Memory Channels that you prefer not to select Menu No. 12 (PRI). monitor during Memory Scan or Group Scan {page 40}. 2 Press [MENU] and turn the Tuning control to select 1 Press [MR] and turn the Tuning control or press “ON”...
3 Press [MENU] to store the new setting or any other SCAN RESUME METHOD key to cancel. The transceiver stops scanning at the frequency (or 4 Press any key other than [MENU] to exit Menu Mode. Memory Channel) where a signal is detected. It then continues or stops scanning according to which Resume Note: To temporarily stop scanning and monitor weak signals, press Mode you have selected.
SELECTIVE CALL Note: CTCSS and DCS do not cause your conversation to be CTCSS AND DCS private or scrambled. It only relieves you from listening to unwanted conversations. You may sometimes want to hear calls from only specific persons or groups. In this case, use Selective Call. This transceiver is equipped with CTCSS (Continuous Tone CTCSS Coded Squelch System) and DCS (Digital Coded Squelch).
CTCSS F Available CTCSS Tone Frequencies ELECTING A REQUENCY 1 Press [F], [MENU] and turn the Tuning control or 42 Tone Frequencies (Hz) press Mic [UP]/[DWN] to select Menu No. 3 (CT). • The current CTCSS frequency appears. 2 Press [MENU] and turn the Tuning control to select your desired CTCSS frequency.
• While scanning, the decimal point of the CTCSS frequency blinks. DCS is similar to CTCSS. However, instead of using • To reverse the scan direction, turn the Tuning control or an analog audio tone, it uses a continuous sub-audible press Mic [UP]/[DWN].
• The available DCS codes are shown in the following table. 104 DCS Codes • While scanning, the decimal point between “DCS” and the DCS code blinks. • To quit the function, press any key. • When a DCS code is identified, the identified DCS code appears and blinks.
DUAL TONE MULTI-FREQUENCY (DTMF) FUNCTIONS This transceiver provides you with 10 dedicated DTMF • When DTMF TX Hold is activated {page 49}, you do not need to continuously press Mic [PTT] to remain in Memory Channels. You can store a DTMF number (16 transmission mode.
DTMF TX H DTMF N TORING A UMBER IN EMORY This function causes the transceiver to remain in 1 Press [F], [MENU] and turn the Tuning control to transmission mode for 2 seconds after you release each select Menu No. 28 (DTMF.MR). key.
6 Repeat steps 4 and 5 to enter up to 16 digits. • The number stored in the channel scrolls across the display, accompanied by DTMF tones from the speaker. 7 Press [MENU] to complete the entry. (DTMF tones are not emitted if Menu No. 33 (DT.M) is set to “OFF”.) •...
4 Press any key other than [MENU] to exit Menu Mode. DJUSTING THE AUSE URATION When this function is activated, you cannot send You can change the pause duration (a space digit) stored DTMF tones using the Mic keypad. DTMF memory in Memory Channels.
AUXILIARY FUNCTIONS APO (AUTO POWER OFF) BEAT SHIFT The transceiver switches OFF automatically if no keys or Since the transceiver uses a microprocessor to control controls are pressed or adjusted for the selected duration. various functions of the transceiver, the CPU clock One minute before the transceiver switches OFF, warning oscillator’s harmonics or image may appear on some beeps sound for a few seconds and “APO”...
1 Press [F], [MENU] and turn the Tuning control to 2 Press [MENU] and turn the Tuning control to select select Menu No. 8 (SSQ). from OFF (default), 125, 250, and 500 ms. 2 Press [MENU] and turn the Tuning control to select “ON”...
3 Press [MENU] to store the setting or any other key to FREQUENCY STEP SIZE cancel. Choosing the correct frequency step size is essential in 4 Press any key other than [MENU] to exit Menu Mode. selecting your exact receive frequency using the Tuning control or Mic [UP]/[DWN].
Note: Setting the brightness to OFF (minimum level 1) will turn the front panel key backlight OFF. TM-281A ( M3 ) 12.5 kHz 25 kHz TM-481A ( M ) UTOMATIC ACKLIGHT When using automatic backlight, the display backlight Note: The market code is printed on the barcode label of the carton will illuminate every time a front panel or microphone box.
LOCK FUNCTION TUNE ENABLE The lock function disables most of the keys to prevent While the Lock function is ON, you sometimes may want you from accidentally activating a function. Transceiver to turn the Tuning control to change the frequency. In Lock is suitable for a typical mobile installation where you this case, turn the Tune Enable function ON.
MICROPHONE PF KEYS (K Programmable Functions EYPAD ODELS • MONI: Monitor function ON/OFF You can access many transceiver settings without using • ENTER: Used to enter a frequency or memory channel transceiver keys or controls. Microphone keys PF/D, number with the keypad MR/C, VFO/B, and CALL/A are programmable with transceiver functions.
NARROW BAND FM OPERATION POWER-ON MESSAGE By default, the transceiver operates in normal FM You can change the Power-on message (a maximum of (±5 kHz) mode for both transmission and reception. 6 characters) when the transceiver is turned ON. You can also operate the transceiver in narrow band FM 1 Press [F], [MENU] and turn the Tuning control to (±2.5 kHz).
6 Press [MENU] to complete the setting and store the Power-on message. 7 Press any key other than [MENU] to exit Menu Mode. Note: If a Power-on message is not set, the transceiver model name appears when the transceiver power is turned ON. 4 Press [MENU] to store the setting or any other key to cancel.
TIME-OUT TIMER The Time-out Timer limits the time of each transmission to a maximum of 3, 5, or 10 (default) minutes. Just before the transceiver stops the transmission, a warning beep sounds. This function is necessary to protect the transceiver from thermal damage and can therefore not be turned OFF.
MICROPHONE CONTROL You can change numerous transceiver settings by operating the Mic DTMF keys. The following table shows what function is switched ON and OFF or which setting is changed by pressing the DTMF keys in the appropriate mode of operation. Storing DTMF Storing Power-on TX Mode...
DTMF tones are not transmitted in TX Mode if the MIC LOCK DTMF Lock function is ON. The Mic Lock function disables the Mic PF keys to When transmitting a stored DTMF number, press Mic prevent you from accidentally changing the transceiver [PTT]+Mic [PF/D], release Mic [PF/D], then press a operation.
OPTIONAL ACCESSORIES PS-60 SP-50B MCP-1A Regulated DC Communications Speaker Memory Control Program Power Supply (Free Software) The MCP-1A can be downloaded at: http://www.kenwood.com/i/products/ info/amateur/software_download.html PG-2N PG-3B KMC-30 MC-59 DC Power Cable DC Line Noise Filter Microphone DTMF Microphone MJ-88 MC-60A...
TROUBLESHOOTING You may return this product for service to the authorized MAINTENANCE Kenwood dealer from whom you purchased it, or any authorized Kenwood service center. A copy of the ENERAL NFORMATION service report will be returned with the transceiver. Please do not send subassemblies or printed circuit This product has been factory aligned and tested to boards;...
• Press any key other than [F] to cancel. NITIAL ETTINGS 3 Press [F] again to reset the transceiver. The factory defaults for the operating frequencies are as follows. • “WAIT” appears momentarily. • TM-281A: 144.000 MHz • TM-481A: 440.000 MHz...
Full Reset Method 2: VFO Reset Method 1: 1 Press [F], [MENU] and turn the Tuning control to 1 With the transceiver power OFF, press [VFO]+[ (Power). select Menu No. 99 (RESET). • The VFO reset confirmation message appears. 2 Press [MENU] and turn the Tuning control to select “FULL”.
TROUBLESHOOTING The problems described in the following tables are commonly encountered operational malfunctions. These types of difficulties are usually caused by improper hook-up, accidental incorrect control settings, or operator error due to incomplete programming. These problems are usually not caused by circuit failure. Please review these tables and the appropriate section(s) of this instruction manual before assuming your transceiver is defective.
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Problem Problem Cause Corrective Action Page Ref. . s l . s l c t i l i t c i l o l l “ t . ” t i x...
Specifications are subject to change without notice due to advancements in technology. General TM-281A (M3 market models) 136 ~ 174 MHz TM-481A (M market models) 400 ~ 470 MHz TM-281A (M3 market models) 136 ~ 174 MHz 400 ~ 470 MHz TM-481A (M market models) 50 Ω...
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Transmitter 65 W (TM-281A)/ 45 W (TM-481A) Variable reactance modulation – ± ± 0 Ω Receiver Double superheterodyne Wide (TM-281A): 0.18 μV or less Wide (TM-481A): 0.20 μV or less v i t y t i Narrow (TM-281A): 0.22 μV or less Narrow (TM-481A): 0.25 μV or less...