Kenwood TM-451A- Manuals

PREPARATION FOR MOBILE OPERATION When operating mobile, do not attempt to configure your transceiver or change Menu settings while driving because it is simply too dangerous. Stop the car first, then make the necessary changes. Also, be aware of local laws pertaining to the use of headphones/headset...

2 Position the transceiver in the bracket to determine the best viewing angle. 3 Insert and tighten the supplied hexagon SEMS screws and washers. There are 2 screws and 2 washers supplied for each side of the bracket. • Double check that all hardware is tightened to prevent vehicle vibration from lo...

If the fuse blows, determine the cause then correct the problem. After the problem is resolved, then replace the fuse. If newly installed fuses continue to blow, disconnect the power cable and contact your dealer or nearest Service Center for assistance. Replacing Fuses Fuse Location Fuse Current Ra...

DC POWER SUPPLY CONNECTION PREPARATION FOR FIXED STATION OPERATION The following diagram illustrates how to make connections to the rear panel of the transceiver. Connect all cables securely so they will not come loose if pulled. In order to use this transceiver for fixed station operation, you will...

► For your transceiver to fully exhibit its performance capabilities, the following optional power supply is recommended:PS-33 (20.5 A. 25% duty cycle). ► Before connecting the DC power supply to the transceiver, be sure to switch the transceiver and the DC power supply off. ► Do not plug the DC pow...

EXTERNAL SPEAKER ACCESSORY CONNECTIONS PACKET EQUIPMENT Use an external speaker with 8 ohms impedance. The jack accepts a 3.5 mm diameter mono (2-conductor) plug. Recommended speakers include the SP-50B and SP-41. Connecting an external speaker automatically cuts off audio to the internal speaker. M...

DATA Connector Pinout Personal computer/dumb terminal Pin Number Pin Name Function 1 PKD Packet data input • Transmit data from TNC to transceiver 2 DE Ground for PKD 3 PKS Packet standby • TNC can use this pin to inhibit the transceiver microphone input while transmitting packet signals. 4 9600D De...

GETTING ACQUAINTED The following sections describe basic functions of the Front Panel controls and buttons, Rear Panel jacks and connectors, microphone buttons and Display indicators. For full explanations of functions mentioned, refer to the appropriate section elsewhere in the manual. FRONT PANEL ...

YOUR FIRST QSO If you tend to discard instruction manuals along with the packaging material....please don’t. The 5 steps below will get you on the air in your first QSO within minutes to allow you to experience the exhilaration that comes with opening a brand new transceiver. After trying the rig fo...

® SHIFT button Selects the transmit frequency offset with respect to the receive frequency {page 491. Also toggles Tone Alert ON or OFF {page 86). (D t ONE/CTCSS button Switches Tone and CTCSS ON or OFF {pages 51 and 74). Also used for selecting the subaudible Tone frequency {page 52}. d) REV (Rever...

REAR PANEL 1 -d) ® ANT connector Connect an external antenna designed for operation on the same band as this transceiver. When making test transmissions, connect a dummy load in place of the antenna. The antenna system or load should have an impedance of 50 ohms. All models accept a male PL-259 coax...

MICROPHONE MC-45DM/45DME © ©UP button (D DWN button Raises or lowers the VFO frequency, the memory channel number, the Tone/CTCSS frequency, the DTSS/Page code, or the Page memory number. Holding either button down causes the action to be repeated, and "fuzzy" logic increases the rate of rep...

DISPLAY ® (D (D ® LOCK\+V+U :L0W .... DUP/ CO S»RF 1 3 5 7 9 OVER MID i REV/—\— +;■< O O O O O O O: ^ V# Ct O 0.0 O 0.0; APO PAG DTSS ^nnO O O DIM . w* -iSEEP----------- ; U l.fSTEP TONE ‘ U m U ^ T O T CTCSS ©LOCK Indicates the Lock function is ON; most Front Panel and microphone buttons and key...

® (D (D ® (S) L0CK:+V+U :L0W mid : r^!3|Q[i0i DUP/ CO REV/- r.:^ilk Wi n O O U C<Wg2 i¿»cttfiw nilfcva I SARF nil OVER O it ó Q O O: U $I,U Q U,U: nii / APÓ DIM------ ' PAG ,«-«BEEP DTSS ^ W M^TEP TONE 3:LI«S.fWTOT CTCss @ - - + Indicates the transmit frequency is offset (different) from the rece...

LOCK: +V +U : LOW MID! REV/-------------------- +/.^ O Q O O O O O: r« DUP.ijCO ! Wm O O O O Wi ItldO.Cl.O OMB Ufcy»lM IslIkIM SARF . { m m Apo ★ DIM PAG -¿ii-BEEP DTSS ■ ■ ■ ■ ■ ■ ■ ■ ■ llll ElZi 'V P ^TEP TON E 1 3 5 7 9 OVER EUD ;!.l« £ff«TOT CTCSS DUP Indicates Full Duplex mode is ON {page 91}. ...

In Receive, acts as an S-meter to indicate the signal strength of received signals. In Transmit, acts as an RF power meter to indicate the relative transmit output power {page 37}. Full scale represents High transmit power. Indicates the transceiver is in Transmit mode with a transmit frequency that...

LOCKiJfV+u’rLOw 'WDi REV/-- 0 --- ------------------------------ y tf.tf V !J^U: DUP CO /UM»T isiiiaM I SARF n 'U O O U'nip ^.\ssm APo- Hw DIM PAG ..-—-—-BEEP DTSS II iJsTEP TONE ER ESo :Lh LU tot ctcss © APO Indicates Automatic Power Off is ON {page 63}. Blinks while accessing Menu A, Automatic Pow...

MENU A CONFIGURATION MenuLabel Description Selections Default Page DIM Display Brightness • 5 illumination levels (d1: brightest) OFF/d4/d3/d2/d1 d2 64 BEEP Confirmation Beep OFF/ON ON 64 STEP Frequency Step Size 12.5kHz/25kHz/5kHz/ 10kHz/15kHz/20kHz TM-251A/E: 12.5 kHz’ TM-451A/E: 25 kHz 35 TOT Tim...

CONFIRMATION BEFORE OPERATION Before proceeding, run through the following checklist to double check that your transceiver is ready to operate; REAR PANEL ANT (Antenna) • Is the correct antenna actually connected? • Is a lightning protector installed for a fixed station? • Are interconnecting coaxia...

FRONT PANEL Controls • Are they preset as shown in the diagram? Microphone • Is a recommended microphone installed? 27

RECEIVING SWITCHING POWER ON/OFF Switch ON the DC power supply, then press [PWR] to switch ON the transceiver. • If operating mobile, simply press [PWR] on the transceiver. • After the on message, the frequency and possibly other indicators appear on the Display. To switch OFF the transceiver, press...

S-Meter Squelch By activating S-meter Squelch, you can set the squelch threshold so the squelch does not open until a signal with the same or greater strength than the S- meter setting is received. 1 Press [F] (1 s) to enter Menu A. 2 Select "S.SQL" {page 22}. • The current S-meter Squelch s...

BAND SELECT The transceiver is equipped with a Main Band for both transmitting and receiving, plus a Sub-band for receiving only. When the Sub-band is selected, [PTT] is disabled, although [TONE/CTCSS] and [REV] are still functional. Full Duplex communication is possible by taking advantage of the r...

Select the Main Band or Sub-band by pressing[F], [REV]. • When the Sub-band is selected, " + U" or" + V" appears as a reminder that the UHF or the VHF Sub­band is currently selected. • After switching bands, the frequency used last on the new band and the frequency step stored in Men...

Programmable VFO You may want to set limits for the minimum and maximum frequencies that are selectable with the Tuning control, for example, to keep your operating within the frequencies set aside by band plans for FM operation. The limits can be set or modified at any time, and are configurable fo...

FREQUENCY STEP SIZE Choosing the correct step size when operating is essential in order to select your exact receive frequency with the Tuning control or microphone [UP]/[DWN]. The best step size is the largest step that will still allow you to select all frequencies on which you plan to operate. Us...

Changes In Displayed Frequencies Changing between step sizes may result in a change of the displayed frequency. When a change occurs, and by how much, is shown in the accompanying charts. This change also affects upper and lower frequency limits selected for the Programmable Band Scan function {page...

MICROPHONE PTT TRANSMITTING SELECTING OUTPUT POWER When ready to begin transmitting, press and hold [PTT] and speak in a normal tone of voice. Speaking too close to the microphone, or too loudly, may increase distortion and reduce intelligibility of your signal at the receiving station. It’s wise, a...

TIME-OUT TIMER (TOT) It is sometimes necessary or desirable to restrict a single transmission to a specific maximum time. This feature can be useful when accessing repeaters to prevent repeater time-outs, or when particularly trying to conserve battery power. Activate TOT anytime you wish to limit y...

A total of 40 memory channels (1 to 40) are available for storing frequencies and related data. Each memory channel can be used either as a simplex channel or split channel for storing any frequency or frequency pair that can be selected on the transceiver. Alternatively, a standard or non-standard ...

3 Turn the Tuning control, or press microphone [UP] or [DWN], to select the desired memory channel. 4 Press [MR]. The selected frequency and associated data are stored in the memory channel. A transmit frequency from a split memory channel or split Call channel is not stored. • If the memory channel...

RECALLING MEMORY CHANNELS ■ Selecting Channels Sequentially This method allows you to select, in numerical order by channel number, all memory channels containing data. 1 Press [MR], • The memory channel used last is recalled. 2 Turn the Tuning control, or press microphone [UP] or [DWN], to select t...

The frequency change is only temporary because it does not alter the stored memory channel contents. You can verify this by changing frequency while a memory channel is selected, selecting a new channel with the Tuning control, and then re-selecting the original channel with the Tuning control. The ...

ERASING MEMORY CHANNELS CALL CHANNEL Although it is possible to overwrite existing data in any of the memory channels with new data, at times you may wish to clear data from memory channels without entering new data. It’s convenient to clear channels no longer used so you can identify channels that ...

Changing Call Channel Contents (Split) 1 Select the desired receive frequency and associated data (Tone, CTCSS, DTSS, etc.) using VFO mode or Memory Recall. 2 Press [F] to select Memory Storage. • "F" and a memory channel number appear. 3 Press microphone [CALL] (1 s). • " - +" appea...

Certain functions cannot be used if Channel Display is activated. The following chart identifies these functions: Non-functional with Channel Display ON Page Ref. Non-functional with Channel Display ON Page Ref. [VFO] 32 Programmable Band Scan Limit Select 59 VFO Scan 59 Programmable VFO Limit Selec...

OPERATING THROUGH REPEATERS Compared to simplex communication, you can usually transmit over much greater distances by using a repeater. Repeaters are typically located on a mountain top or other elevated location. Often they operate at higher ERP (Effective Radiated Power) than a typical base stati...

The TM-251E Automatic Offset is programmed as follows: European Versions 145.600 145.800 MHz S: Simplex 50 If you need to use a non-standard offset for any reasonil a value can be selected from Menu A as follows: 1 Press [F] (1 s) to enter Menu A. 2 Select" - +" {page 22}. • " - +" b...

REVERSE FUNCTION TONE ACCESS Each press of [REV] switches the receive frequency and the transmit frequency. When used while monitoring a repeater, it’s possible to check the signal strength of a station accessing the repeater. If the station’s signal is strong, it’s best to move to a simplex frequen...

Selecting a Tone Frequency Often a Tone frequency is required to access repeaters. For example, 88.5 Hz may be needed in the U.S.A. or Canada, and 1750 Hz is used in Europe. The Tone frequencies listed below can be selected. No. Freq (Hz) No. Freq (Hz) No. Freq (Hz) 01 67.0 14 107.2 27 167.9 02 71.9...

European Versions To send 1750 Hz, "1750" must first be selected from the Tone frequency list by using the "Selecting a Tone Frequency" {page 52} procedure. A 1750 Hz Tone is then transmitted by pressing [TONE/CTCSS] or microphone [PF]. If you prefer, this function can be assigned to...

DUAL TONE MULTI-FREQUENCY (DTMF) MEMORY The following DTMF functions require an MC-45DM/DME DTMF microphone or a TH-7 transceiver. ■ Making DTMF Calls To make a DTMF call, hold down the microphone [PTT] and press [0] to [9], [ A ] , [B], [C], [D], [*], or [# 1 . • The microphone is muted and the cor...

Confirming Stored DTMF Numbers 1 Press [REV] + POWER ON to enter Menu B. 2 Select Menu No. 65 {page 24}. 3 Turn the Tuning control, or press microphone [UP]/[DWN], to select "P---------- ". 4 Press microphone [CALL]. • "-------- " disappears. *».« C T» * n ( t jLi tU I.Mat’HI r r LI ...

SCAN Scan is a useful feature for hands-off monitoring of your favorite frequencies. After becoming comfortable with how to use all types of Scan, the monitoring flexibility gained will increase your operating efficiency. This transceiver provides 5 types of Scan as follows: Scan Type Purpose Memory...

SCAN RESUME METHODS SELECTING SCAN RESUME METHOD Before using Scan, it’s necessary to decide under what condition you want your transceiver to continue scanning after detecting and stopping for a signal. You can choose Time-operated Scan or Carrier-operated Scan. The default is Time-operated Scan. ■...

Memory Scan allows all memory channels containing data to be scanned regardless from which band the frequencies were stored. 1 Press [MR] (1 s). • Scan starts with the channel last recalled, then scans through the memory channels in the same direction last used for scanning. • The default direction ...

Band Scan allows you to scan all frequencies from the lowest frequency to the highest frequency on each band that your transceiver is capable of receiving. The currently selected frequency step size for each band is used. 1 Press [VFO] to select VFO mode. 2 Select the band that you want to scan by p...

5 Select Menu B, No. 60. • The current lower limit appears. 6 Turn the Tuning control, or press microphone [UP] or [DWN], to select the desired lower limit. <,|C inn /V-l. l U u ^ , I 3 • 7 • OVER » I U LI 7 Exit Menu B. Note: ► The upper limit is set first above; however, either lower or upper l...

AUXILIARY FUNCTIONS LOCK Occasionally, you may want to lock the buttons, keys and the Tuning control to prevent accidentally changing any transceiver settings. This transceiver has 2 lock functions for this purpose. ■ Transceiver Lock Press [F], [LOW]. • "LOCK" appears when the Transceiver L...

AUTOMATIC POWER OFF (APO) After a programmable time period elapses with no key entries, APO turns OFF the power; however, 1 minute before the power turns OFF, "APO" starts blinking and a series of warning tones sound. If the squelch opens or any keys are pressed during the time period while ...

BEEP TONE DISPLAY DIMMER The transceiver beeps each time you press a button or key. Also, pressing [PTT] generates a beep any time transmission is not possible on the frequency selected. For example, the transceiver beeps when [PTT] is pressed while the Sub-band is selected or while a transmit offse...

While using Tone/CTCSS, DTSS or Page, there are several options available for ho\w information appears on the Main Display and the smaller Sub-display. Review the following chart to decide the arrangement you prefer, then select your choice from Menu A. DISPLAY MODE Menu A Selection Main Display Sub...

► If using S ub 2 w hile Tone is O N , the T oneJC T C S S frequency m ust be selected by turning the T uning control or pressing m icrophone [U P ]J[D W N J. Y ou cannot select a new T one/C T C S S frequency by u sing [F], [T O N E /C TC S S ]. ► T o change the operating frequency w hile using S u...

REMOTE CONTROL This feature allows numerous transceiver functions to be changed conveniently from a microphone such as the MC-45DM or MC-45DME without using the Front Panel buttons or controls. These microphones are equipped with a DTMF keypad that is used in conjunction with other keys and buttons ...

1 Press [REV] + POWER ON to enter Menu B. 2 Select Menu No. 50 {page 24}. • The current Remote Control status appears. n r r u * f I « T • oven t t j i j O C >■* I > tJt.m C f * .# LI 3 Select a status. • See chart above. • Default: OFF 4 Exit Menu B. N ote: R em ote C ontrol cannot be used if...

Configuring the PF Keys The Programmable Function (PF) keys are the horizontal row of 4 keys located on the face of the microphone. These keys are identified as follows: Key Label General Key Name Default Function To Restore Default Function PF PF1 Monitor’ [F]+ POWER ON MR PF2 Memory Recall Follow ...

Memory Channel Entry Memory Channel Entry is similar to Frequency Entry except this function is used when Memory Recall is selected. If you want to choose a memory channel quickly without scrolling through many other channels, this is the method to use. 1 Press [MR] to select Memory Recall. 2 Press ...

USING CTCSS CONTINUOUS TONE CODED SQUELCH SYSTEM (CTCSS) The CTCSS feature is available only when the TSU-8 CTCSS unit is installed. CTCSS functions by using subaudible tones that are superimposed by a transmitter on a transmitted signal to control a receiver’s squelch. When used in combination with...

DUAL TONE SQUELCH SYSTEM (DTSS) DTSS provides a more refined method than CTCSS to selectively communicate with specific stations. A total of 1000 3-digit DTMF (Dual Tone Multi-Frequency) codes are available to be used as addresses for stations with which you want to communicate. These codes can be c...

STORING DTSS CODES You can store a DTSS code from 000 to 999 by using the Tuning control or the microphone. Be aware that audible DTMF tones from other transceivers near you may be picked up by your MC-45DM/DME or TH-7 microphone element. If so, this could prevent the following function from working...

2 Select Menu No. 53 {page 24}. • The current Delay Time appears. 71 C -I Jf 11 MRF 1 > • 7 • oven c :» Jr Jr 3 Select a time value. • The times available are 350 or 550 ms. • Default: 350 ms 4 Exit Menu B. Note: ► DTSS cannot be used with some repeaters. y The delay time selected using Menu No. ...

This procedure allows you to change the default DTSS code required to use the Message Playback function, 1 Press [REV] + POWER ON to enter Menu B. 2 Select Menu No. 73 {page 24}. • The current Message Playback DTSS code appears. Setting Message Playback DTSS Code V Iv _ Cl I f j -vt Jl I-I f .r 1 $ ...

PAGE OVERVIEW Similar to DTSS, Page uses DTMF codes to address a single station or a group of stations. Page is useful when waiting to receive a call from a specific station. A common Group Page code and individual Station codes should be agreed on in advance. You can select codes from the range 000...

Turn the Tuning control, or press microphone [UP]/[DWN], to select Page memory A. • Alternatively, if your microphone is equipped with a DTMF keypad, the Page memory can be entered by using the keypad numeric keys including [A]. After entering the Page memory, the Page code stored inthat memory appe...

CALLING 1 Tune to the prearranged frequency. 2 Press [DTSS] (1 s). • "PAG" appears. • Repeating this step toggles the Page function ON and OFF. 3 Press [F], [DTSS] to select Code Select. • The small Page memory "P" and "PAG" start blinking. 4 Turn the Tuning control, or press...

RECEIVING 1 Tune to the prearranged frequency. 2 Press [DTSS] (1 s). • "PAG" appears. You are ready to receive a call addressed with your Station code or a Group code. If no signal is received for more than 2 seconds after a Page has opened the squelch, the squelch then closes. ■ Receiving a...

PAGE ANSWER-BACK PAGE CODE AND REPEATERS Page Answer-back is a confirmation signal consisting of your Station code sent by your station back to the station that initiated a Page call. The purpose is to inform the other station that your station received the Page call. Your station only sends the Ans...

LOCKING-OUT CODES AUTO PAGE CANCEL The following explains how to inhibit the transceiver from receiving specific Page codes. Although the codes are locked-out from the receiver, the transmitter still transmits a Page on the locked out channels. 1 Press [DTSS] (1 s). • "PAG" appears. 2 Press ...

OPEN PAGE When both this function and Page are ON, any signal opens the squelch; however, if a correct Page code is received, the calling station’s code appears on the Display. This feature is beneficial when you want to generally monitor activity on a frequency but you want to be especially sure no...

TONE ALERT Tone Alert provides an audible alarm to indicate when someone is transmitting on the frequency you are monitoring. Tone Alert is an effective partner with CTCSS, Page, or DTSS. When the correct signaling comes through, your transceiver beeps to alert you of an incoming call from a specifi...

CHANGING THE ALARM TONE Depending on where your station is installed and the ambient noise at your station location, you may want to change the default alarm signal that sounds when Tone Alert detects an incoming call. You have a choice of 3 alarm signals that may be selected as follows, 1 Press [F]...

MESSAGE RECORDING Although the Page/Tone Alert combination is useful to keep track of who called you and when, a better idea is to make an audio recording of a caller’s message to you. The Message Record feature serves as a digital answering machine for your on-air activity in the same way tape reco...

SELECTING THE RECORDING MODE Sometimes you may want to continuously record the last audio that opened your transceiver squelch. This mode is similar to a tape that records continuously and automatically in an endless loop over previous messages, saving only the latest message. This method is useful ...

PLAYBACK Playback of the recorded messages always begins with the newest message first, i.e. the order of playback is Message 2 followed by Message 1. After playback, the transceiver returns to standby ready to record again when the squelch opens. Press [SHIFT] (1 s). • The newest message is played ...

FULL DUPLEX OPERATION Full Duplex allows you to have relaxed contacts that more closely resemble conversations that you might have with somebody in person. Since each party is transmitting on a different band, there is no necessity for either party to turn OFF their transmitter while listening, alth...

PACKET OPERATION One of the most exciting benefits of owning an FM transceiver nowadays is the ability to use it for VHF or UHF Packet radio. TM-251/451 transceivers are ideal, due to their small size, for operating Packet portable from a local mountaintop, for example, even if the transceiver is no...

MAINTENANCE GENERAL INFORMATION Your transceiver has been factory aligned and tested to specification before shipment. Under normal circumstances, the transceiver will operate in accordance with these operating instructions. All adjustable trimmers, coils and resistors in the transceiver were preset...

TROUBLESHOOTING The problems described in this table 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, and are not caused by a circuit failure....

Problem Symptom Probable Cause Corrective Action Page Ref. No sound comes from the speaker even though the VOL control is turned clockwise. 1 The squelch is closed. 2 DTSS is ON ("DTSS" is visible); DTSS codes that you are receiving are different from the code set in your transceiver. 3 Page...

OPTIONAL ACCESSORIES MC-45/45E Multifunction Microphone MC-45DM/45DME Multifunction Microphone with DTMF Keys TSU-8 CTCSS unit ME-1 Memory Expansion Unit MB-12 Mobile Mounting Bracket MB-201 Mobile Mounting Bracket SP-41 Mobile Speaker SP-50B Communications Speaker 102

OPENING THE TRANSCEIVER 1 Turn off the power to the transceiver. INSTALLING OPTIONS INSTALLING THE TSU-8 CTCSS UNIT 1 Open the transceiver. 2 Remove the 2 screws from the upper cover, then lift up the rear of the cover to remove it. • Five tabs hold the front and sides of the upper cover. 2 Hold the...

INSTALLING THE ME-1 EXPANSION MEMORY UNIT 1 Open the transceiver (page 104J. 2 Hold the ME-1 unit with the large 1C facing upward and insert the connector on the ME-1 unit into the 5-pih ¿6hrt66t6r' ¡¿b^led "ME-1". 3 lP-3^

SPECIFICATIONS General TM-251A/251E TM-451A/451E Frequency range Main band 144.000-147.995 MHz’ 438.000-449.995 MHz^ Sub-band (receive) 438.000-449.995 MHz^ 144.000-147.995 MHz^ Mode F3E Antenna impedance 50 D. Usable temperature range -20“C - +60°C Power supply DC 13.8 V±15% (11.7 V - 15.8 V) Groun...

Transmitter TM-251A/251E TM-451A/451E Power output High 50 W 35 W Mid Approx. 10 W Approx. 10 W Low Approx. 5 W Approx. 5 W Modulation Reactance Spurious emissions -60 dB or less Maximum frequency deviation ±5 kHz Audio distortion (at 60% modulation) 3% or less Microphone impedance 600 n Receiver Ci...

GLOSSARY APO (Automatic Power Off) A function that automatically turns OFF the transceiver after some period of inactivity. Auto Page Cancel A function that automatically switches OFF the Page function after Page codes have been transmitted. The purpose is to avoid sending Page codes at the start of...

Memory Storage A function that saves an operating frequency and associated data into a memory channel. See "Memory channel". Memory ->■ VFO Transfer A function that records the current memory channel data in the VFO then selects VFO mode. This transfer action does not affect the data stor...

QUICK REFERENCE GUIDE This guide assumes your transceiver is currently in VFO mode. Function Menu Action Page Power ON/OFF — [PWR] 28 AM/FM Mode’ A"spade" Menu Set-up 31 Automatic Power Off (APO) A "APO" Menu Set-up • After APO turns transceiver OFF; [PWR] 63 Autopatch — See DTMF and...