Kenwood tkr 750 руководство

VHF FM REPEATER

TKR-750

SERVICE MANUAL

REVISED

INTRODUCTION

SCOPE OF THIS MANUAL

This manual is intended for use by experienced technicians familiar with similar types of commercial grade communications equipment. It contains all required service information for the equipment and is current as of the publication date. Changes which may occur after publication are covered by either Service Bulletins or Manual Revisions. These are issued as required.

PERSONNEL SAFETY

The following precautions are recommended for personnel safety :

•DO NOT transmit until all RF connectors are verified secure and any open connectors are properly terminated.

•SHUT OFF and DO NOT operate this equipment near electrical blasting caps or in an explosive atmosphere.

•This equipment should be serviced by a qualified technician only.

ORDERING REPLACEMENT PARTS

When ordering replacement parts or equipment information, the full part identification number should be included. This applies to all parts : components, kits, or chassis. If the part number is not known, include the chassis or kit number of which it is a part, and a sufficient description of the required component for proper identification.

SERVICE

This radio is designed for easy servicing. Refer to the schematic diagrams, printed circuit board views, and alignment procedures contained in this manual.

Merchandise

received

Choose the type of transceiver

See page 11.

A personal computer (IBM PC or compatible), programming interface (KPG-46), and programming software (KPG-66D) are required for programming.

See page 42.

The RX RF BPF (L2,L3,L5,L6,L7 on TX-RX unit A/2) must be aligned to obtain the maximum sensitivity at a programmed frequency.

1 Speaker

2 CH/STATUS Display

Two, 7-segment digits display the channel number or status.

3 VOLUME control

Rotate to adjust the volume.

4 DC source switch

5 Dc source indicator

Lights green when DC source is applied from the DC 13.6V jack (DC 13.2V jack on E type versions). Lights red when DC source is applied from the BACK UP battery terminal.

6 MIC jack

Connect a microphone to this 8-pin modular jack.

7 Programmable Function keys

Press these keys to activate their programmable functions.

8 BUSY indicator

Lights green while a signal is being received.

9 TX indicator

Lights red while transmitting.

Connect a TX antenna or a duplexer to this receptacle.

2 CONTROL I/O jack

Connect an external programming device or repeater controller to this DB-25 interface.

3 FUSE

Insert 15 A blade fuses into these fuse holders.

Connect a 13.6 V (K type) or 13.2 V (E type) DC power supply to this jack.

6 BACKUP battery terminal

7 TEST/SPKR jack

Test input/output jack. Connect an external speaker to this jack.

2. Two 7-segment LED displays

•Channel display (1~16) : While operating normally in user mode.

•When the displayed channel is contained in scan sequence, the right side decimal point is displayed.

• “E2” is displayed when the channel data is not written.

•“E3” is displayed when PLL is unlocked. Receiver PLL unlocked = flashing BUSY LED. Transmitter PLL unlocked = flashing TX LED.

5. Simplex/Duplex Operation

The Simplex/Duplex function is used to specify whether the channel is used as simplex (receiver muted during transmit) or duplex (receiver unmuted during transmit). If the channel has same TX/RX frequency, it can operate only in Simplex mode.

6. Repeater/Base Station Operation

The Repeat function is used to specify whether the channel is used as a repeater or as a base station. A repeater simultaneously and automatically re-transmits its received audio, a duplex base station has independent simultaneous transmit and receive paths, a simplex base station are mutually exclusive transmit and receive paths.

7. Signalling Feature

7-1. Multiple QT/DQT

The TKR-750 can function as a multiple-QT/DQT decode/ encode unit for operation as a community repeater or mul- tiple-QT/DQT base station. Two Multi Tables, called Main and Sub, can be created, each consisting of 16 decode/encode combinations.

The Multi Table function enables the TKR-750 to decode any one of the 16 QT/DQTs pre-programmed into the Multi Table. When receiving a signal (repeater operation), the repeater uses the QT/DQT encode which corresponds to the decoded QT/DQT as set in the Multi Table. In the Multi Table, signalling pair of “No.1” (first column) is defined as “Primary”. A receiving signalling (if it is contained within No.1 to No.16) is defined “Current”.

From No.2 to No.16, signalling pairs that can be changed between “Main Table” and “Sub Table” using AUX I/O Ports 1-4 are assigned as “Multi Table Select” and the Multi Table Main, the Multi Table Sub or the Multi Table Main/Sub function is executed. When AUX I/O Ports 1~4 are set for “Multi Table Select”, these are 4 bit Binary Coded Decimal (BCD) inputs .AUX I/O 1 is a least significant bit (LSB), and “1101” input (LSB on the right side) signifies the Table No.2 and “1100” input signifies the Table No.3.

7-2. Encode Tone in Multiple

When Local Microphone PTT or External PTT is active while the repeater is in use or the duplex-base station is receiving, the encode signalling is determined according to Encode Tone in Multiple function. The simplex-base station always transmits the “Primary” encode QT/DQT.

Current : When any PTT as described above is active while the repeater is in use or the duplex-base station is receiving, the “paired” encode QT/DQT associated with receiving QT/DQT is transmitted. When any PTT is active while the repeater or the duplex-base station is in idle period, the “Primary” encode QT/DQT is transmitted.

Primary : When any PTT (provided that the Priority of any PTT is higher than the Priority of Repeat PTT) is active while the repeater is in use, the encode QT/DQT changes “paired” encode QT/DQT to “Primary” while continuing to transmit. When any PTT is active while the repeater is in idle period, the “Primary” encode QT/DQT is transmitted. In the base station, the “Primary” encode QT/DQT is always transmitted regardless of the receiver status.

7-3. QT Reverse Burst Time

During repeat with QT tones, the repeater re-transmits a phase-shifted burst of the QT tone (“reverse burst”) when it detects the radio using the repeater has un-keyed and also sent a reverse QT burst (squelch-tail elimination). This mutes a receiving radio’s speaker audio before its receiver circuit shuts off causing squelch tail noise in the speaker audio. The TKR-750 can select the time between 140 to 200 ms that the QT reverse burst is sent. Typically this time should not have to be adjusted from the default value. The transmission of the QT reverse burst can be also inhibited if the QT Reverse Burst function is set to “No”.

7-4. DQT Turn Off Code Time

During repeat with DQT tones, the repeater re-transmits a specific turn-off code when it detects the radio using the repeater has un-keyed and also sent the turn-off code (squelch-tail elimination). This mutes a receiving radio’s speaker audio before its receiver circuit shuts off causing squelch tail noise in the speaker audio.

The TKR-750 can select the time between 140 to 200ms that the DQT turn-off code is sent. Typically this time should not have to be adjusted from the default value.

7-5. Off Hook Decode

The TKR-750 is able to decode QT/DQT regardless whether the local microphone is in the onor off-hook condition. When the Off Hook Decode function is enabled, the TKR-750 is capable of QT/DQT decode even though the microphone is in the off-hook condition (or a local microphone is not installed).

8. Scan Feature

8-1. Scan Operation

Providing that the TKR-750 contains two or more non-pri- ority ADD channel or one or more non-priority ADD channel and Priority channel, it starts scanning once the Scan On function is executed and displays “SC” on the 7-seg LED. Scanning stops temporarily if any following conditions be come valid.

1)if a RF carrier and a valid QT/DQT is present. The receiving channel number is displayed and the received audio is heard from a speaker.

2)if a RF carrier is present, providing that the Monitor On function is executed.

3)if the Squelch Off function is executed. Scanning stops on the channel being scanned when Squelch Off is executed, the channel number is displayed and the received audio is heard from a speaker.

4)if a local microphone’s hook is in off hook status, providing that the Off Hook Scan function is set to Disable. Scanning stops on the Revert channel, but the audio is not heard until a valid signal is received.

When the received call is ended, scanning automatically resumes after the period set in Dropout Delay Time function has expired. When the Scan Off function is executed, the TKR-750 inhibits scanning and displays the selected channel.

8-2. Scan Sequence

1)Normal Scan : When no Priority channel is set, scanning of ADD channels is done in ascending order.

2)Single Priority Scan : The Priority channel is set as either a fixed channel or a selected channel. When Priority channel is set, Priority channel and non Priority channel are scanned by turns. When scanning stops on the non Priority channel, calls from the Priority channel are still checked at set intervals while scanning is stopped. This operation is called Look Back and the interval period is selected by the Look Back Time function.

8-3. Revert Channel

The Revert channel is a channel that is used to transmit during scanning. The time from the end of transmission on Revert channel to the time scanning automatically resumes is set in Dwell Time function. The Revert channel types are Last Called, Last Used, Selected, Selected + TalkBack, Priority, and Priority + TalkBack.

1)Last Called : The TKR-750 reverts to the channel upon which a call was last received even if scanning has resumed (power on default = selected channel).

2)Last Used (with TalkBack) : The TKR-750 reverts to the channel that was last transmitted on (power on default = selected channel). However, if a call is received on a channel other than the last transmit channel and PTT is pressed before scanning resumes, the transceiver “talks back” on the current receive channel.

3)Selected : The transceiver reverts to the channel set by the function prior to scan initiation.

4)Selected+TalkBack : The TKR-750 reverts to the channel set by the Channel ‘X’ functions or Channel Select function prior to scan initiation. However, if a call is received on a channel other than the selected channel and PTT is pressed before scanning resumes, the transceiver “talks back” on the current receive channel.

5)Priority : The TKR-750 always reverts to the Priority channel.

6)Priority+TalkBack : The TKR-750 always reverts to the Priority channel. However, if a call is received on a channel other than the Priority channel and PTT is pressed before scanning resumes, the transceiver “talks back” on the current receive channel.

9. CW ID and Message

The TKR-750 contains internal automatic station identifiers. The CW ID (Morse code) is set and transmitted on a per-channel basis. The CW ID is transmitted when the interval period is reached (TX Interval Time function), the channel is changed (CW ID on Channel Change function) or CW ID Onfunction is executed. When CW ID is activated by any functions described above, it is actually sent after the total time of TX Delay Time (not applied to CW ID On function) and CW Modulation Delay Time has expired. TX Delay Time is a period from CW ID is activated to the transmitter is keyed.

CW Modulation Delay is a period from the transmitter is keyed to the CW ID tone is sent. The CW ID tone is routed to the Receive Audio (RA) port and a speaker if the Send CW ID to RA function is set to Yes. The TKR-750 contains 8 message banks for CW Message. CW Message 1 to 8 is transmitted on the current channel when the CW Message 1 to 8 On function is activated, respectively.

13. Take Over

The Take Over function is used to disable the external wireline control of the repeater. When Take over function is enabled, the external AUX inputs and Outputs, transmit audio inputs and receive audio outputs, External PTT and External Monitor lines are disabled. All AUX Input functions assigned to any AUX Input stay in their current state. However External PTT and External Monitor switch to the “Off” state.

14. Test Tone

The Test Tone is a single-frequency audio sine wave and is turned On and Off by toggling Test Tone On/Off functions. The transmitter can be modulated without a local microphone by using the test tone. When Test Tone On function is executed and any PTT is activated, the TKR-750 transmits the test tone with mic mute and also routes the test tone to RA port.

15. RF Power

The TKR-750 is able to switch transmission output on a per-channel basis. When the TX High Power function is enabled, the transmission output is set to high power.

10. PTT Priority

A number of keying sources can be used to cause the TKR-750 to transmit.

The transmit audio path is switched according to their keying sources and when PTTs is simultaneously activated, the transmit audio path related to the PTT with higher priority is given priority. These are Local Microphone PTT, External PTT, and Repeat PTT.

11. Time Out Timer

The Time Out Timer function determines the period of time users can continuously transmit. When the selected period expires, the transmission is inhibited.

12. Repeat Hold Time

The Repeat Hold Time (hang timer) function is used to prevent the repeater from being repeatedly keyed and unkeyed in response to short message traffic. When a mobile transceiver unkeys, the repeater’s Hold Timer allows the repeater to continue transmitting for a brief period while waiting for a responding end user. If no valid QT/DQT is detected within the Hold Timer period, the transmitter is allowed to unkey. This function determines the period of time that the transmitter is allowed to remain keyed after the loss of a valid QT/DQT received signal.

16. Fan Action

The TKR-750 has a cooling fan. The Fan Action function determines whether the fan is continuously operated or operates in response to high temperatures only.

17. AUX Input and Output

There are 6 programmable AUX I/O Ports 1~6 (pins 20~25) and 3 programmable AUX Input Ports 1~3 (pins 4~6) on the rear 25 pin D-Sub connector (CONTROL I/O) and 5 programmable AUX Output Ports 1~5 (pins 10, 11, 13~15) on the rear 15 pin TEST/SPKR connector.

The 6 programmable AUX I/O pins are primarily intended for remote control interfaces. Each AUX I/O Port can be set for AUX Input, AUX Output, remote Channel Select or Multi Table Select types. The AUX Input Port can be set execute a single input function or a set of up to three functions when the port is activated. If the port type for an AUX I/O Ports 1~6 is set for “AUX Input”, it will also appear AUX Input window for function programming. The input logic is fixed as active Low.

The AUX Output Port can be set execute a single output function. If the port type for an AUX I/O Ports 1~6 is set for “AUX Output”, it will also appear AUX Output window for function programming. The output logic of AUX Output can be set as either active High or active Low by the Logic Type function. Active High outputs a High (5V) when the programmed condition becomes valid, active Low outputs a Low (0V) when the condition becomes valid.