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Related Manuals for RELM SMX920
Summary of Contents for RELM SMX920
- Page 1 Base Station and Repeater Technical Manual SMX920...
- Page 3 Service: (800) 422-6281 www.relm.com Manual Revision 08-05 In order to continually improve our products, Spectra Engineering Pty Ltd and RELM Wireless Corporation reserves the right to alter, without notice and at any time, the equipment and specifications described in this document.
- Page 4 SMX920 Base Station & Repeater Technical Manual This page left blank intentionally Revision 08-05...
- Page 5 SMX920 Base Station & Repeater Record Of Changes Any changes to this manual are recorded on this list. RELM Wireless may issue replacement pages to you from time to time. If any updates are issued, you will also receive a replacement for this page.
- Page 6 Only the SMX920’s self contained power supply, if installed, contains dangerous mains voltages within. Normal operation and use of the SMX920 does not expose the operator or service technician to high voltage parts. The power supply is isolated from and maybe removed safely from the main chassis.
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Page 7: Table Of Contents
RX Signal Processing ..............17 5.2.4 RF Power Control ..............18 5.2.5 User Interface................18 Power Amplifier Module................. 18 SMX920 Base Station Fault Finding Procedure ........... 20 SMX920 Base Station ................20 6.1.1 Transmitter Section ..............20 6.1.2 Receiver Section ................. 21 Microcontroller Section of PCB.............. - Page 8 Software Menu System..............34 8.3.2 Interfacing Information .............. 35 SMX920 Specifications................35 8.4.1 Operating Frequency Bands ............35 8.4.2 General..................36 8.4.3 Transmit ..................37 8.4.4 Receive ..................38 8.4.5 Ancillaries .................. 38 SMX920 Model Number Configuration Guide........39 RELM/ BK RADIO...
- Page 9 Table 5-1 Microprocessor Port Parameters..............16 Table 7-1 Peak Deviation Settings ................28 Table 7-2 Nominal Deviation ..................30 Table 8-1 SMX920 Interface Connectors ..............31 Table 8-2 SMX920 Accessory Socket Pinout..............31 Table 8-3 SMX920 Test Points ..................32 Table 8-4 Rs232 Pin configuration ................
- Page 10 List of Figures Figure 1-1 SMX920 Horizontal andVvertical types of Front Panel LEDs....... 3 Figure 1-2 SMX920 Rear Panel with Power Supply and Duplexer fitted....... 5 Figure 7-1 Under (increase level) ................. 29 Figure 7-2 Over (decrease level)................... 29 Figure 7-3 Correctly Aligned Waveform...............
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Page 11: General Description
This permits the Technician to diagnose problems while either still connected in the chassis or powered simply and independently on the test bench. The flexibility of the SMX920 series allows it to be configured for a wide range of applications without removing any covers. -
Page 12: Physical Description
♦ Programmable channel spacing ♦ Low receiver standby current consumption ♦ Flash upgradeable In addition, the SMX920 can be fitted with options, not being limited to the following: ♦ Simplex antenna changeover relay ♦ Power supply ♦ Duplexer ♦... -
Page 13: Front Panel
1.1.1 Front Panel 1.1.1.1 Standard Front Panel The SMX920 front panel comes in both horizontal and vertical types, this can be see in the illustrated below. The front panel provides the user with real time status of the SMX920. Figure 1-1 SMX920 Horizontal andVvertical types of Front Panel LEDs ♦... -
Page 14: Table 1-1 Led Functions
Refer to Section 2.2.1.3 for channel select method. Table 1-1 below explains the functions of the front panel LED's. Each LED indicates the status of the SMX920 in real time. As the LEDs are also software programmable, it is also best to check the settings in software. -
Page 15: Table 1-2 Rear Panel Connections
The rear panel image shown has the internal Power supply fitted, alternatively the SMX920 can be ordered without the Power Supply or it can be retrofitted at a later date should this be required. In the case of power being fed externally, the flying lead is then routed out through the cable clamp grommet supplied with all units. -
Page 16: Module Functional Description
1.2 Module Functional Description 1.2.1 RF Module and Main Controller Assembly The SMX920 consists of a full duplex RF module with its own shielded metal housing and a Main Controller board integrated on a single PCB. Using advanced yet simplified circuit designs, the size and complexity is reduced. This affords a number of advantages including;... -
Page 17: Power Amplifier Module
An on onboard EEPROM stores all of the user channel related data such as frequencies, CTCSS tones etc. A serial port at the Microphone accessory socket of the SMX920 provides access to the Controller card software configurations for the purpose of the user to create and change this channel related information. -
Page 18: Installation And Operation
0.5V volt drop at this current. 2.2 Operation The SMX920 can operate in local control Base Station mode or Repeater mode via the front panel controls. Setting up the SMX920 to operate in the wanted settings is straightforward and involves one main step. -
Page 19: Table 2-1 Micro Controller Jumper
2.2.1.3 Select Operating Channel The SMX920 has a channel capacity of 255. The RF and CTCSS frequencies for each channel are programmed using the radio configuration menu system channel edit screen. There are two ways of selecting the operating channel. -
Page 20: Adjustments
2.2.2 Adjustments The SMX920 has adjustable parameters which are under the control of the Micro Controller. These comprise of TX power, TX VCO deviation, TX reference oscillator deviation and TX reference oscillator frequency. All of these are adjusted with the aid of the built-in radio configuration menu system and all except TX power should only be adjusted as a part of a full TX VF path alignment procedure. -
Page 21: Standard Features
3.2 Programmable DCS / CTCSS encoder / decoder 3.2.1 Description The SMX920 is fitted with a full duplex DCS / CTCSS encoder / decoder. There are 83 DCS codes available. Any standard DCS code or CTCSS tone may be assigned to any of the transmit or receive channels through the channel edit screen in built-in radio configuration menu system. - Page 22 SMX920 Testing: 1. Connect a Communications Cable to the SMX920. 2. Set SMX920 into Diagnostics mode using the built-in radio configuration menu system. The SMX920 will periodically update the terminal screen with the selected channel, the power supply voltage and various other diagnostic information.
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Page 23: Options
2. Remove the existing Receiver coaxial feeder cable assy. 3. Install the relay assy into the SMX920 with the relay coil on the opposite side of the relay to the DC power connector. Secure with the 2 of 3x8mm screws provided. - Page 24 4. Set the test set to measure Tx modulation level and Inject into RJ45 pin 4 with a audio generator output level of –10dBm. 5. PTT the SMX920 (RJ45 Pin 3) and measure the Tx Power and modulation depth. Ensure that the coaxial relay operates correctly and that the full RF power is measured on the test set.
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Page 25: Technical Description
Technical Manual Installation and Operation 5. Technical Description The internal design of the SMX920 is of a modular nature allowing for simple configuration and maintenance while ensuring minimal downtime. 5.1 Exciter Section RF from the VCO is at a nominal level of +3 dBm is applied to the fractional-N synthesiser main divider input. -
Page 26: General Radio Management
SMX920 Base Station & Repeater Technical Manual and VF processing. The Received Signal Strength Indication (RSSI) is buffered and connected to the Micro Controller. RF from the VCO at a nominal level of +3 dBm is applied to the fractional-N synthesiser’s main divider input. -
Page 27: Tx Signal Processing
The output of the comparator is fed to the logic and microprocessor. Like the Transmitter Signal processing circuitry, the SMX920 uses the technique of calibrating all Receive Signal level alignments in the Wide Band mode (25kHz channel spacing) for maximum accuracy. -
Page 28: Rf Power Control
RF power rise characteristic. 5.2.5 User Interface All user interfaces to the SMX920 except the TX RF connections is made by way of the Main Controller board. ♦ Output latch IC4 drives the six LED indicators on the front panel. The function is described in Section 1.1.1. - Page 29 PCB artwork. The sampled RF energy is rectified to provide a proportional DC voltage output. The PTT signal enables the amplifier circuit by providing bias to the transistors. A thermistor TS1, physically located on the PA heatsink monitors the heatsink’s temperature and is monitored by the Micro Controller. RELM/ BK RADIO...
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Page 30: Smx920 Base Station Fault Finding Procedure
5 (Earth) & 3 (PTT) of the RJ45 connector at the front of the radio to ground. ♦ If the output power of the SMX920 is LOW then using the in built menu system check that the ‘Transmit Power’ control is not on a low setting. ♦... -
Page 31: Receiver Section
♦ Check for an audio signal @ -10dBm on pin 1 of the RJ45 connector on the front of the SMX920. ♦ If there is an audio signal @ -10dbm check the receiver for correct SINAD, SNR, Audio Distortion and Mute operation. -
Page 32: Microcontroller Section Of Pcb
SMX920 Base Station & Repeater Technical Manual 6.2 Microcontroller Section of PCB Check fuse. If blown, replace with a 5x20 mm 3A fast blow fuse. Check jumper is in the correct position for operation. 6.3 Receiver Section 6.3.1 VCO Locking ♦... -
Page 33: Exciter Module
Connect the input of the PA to signal generator with the RF output switched off. ♦ With PTT off measure the +13.8V supply at the Source of the driver and output FET . If out of spec then check voltage at CN2-2, no volts then check supply cable. RELM/ BK RADIO... - Page 34 SMX920 Base Station & Repeater Technical Manual ♦ With PTT ON measure the PA bias current at the Gates of the FET’s. The Bias current is band dependent. This is done by monitoring the current drain of the whole PA with CN1 disconnected. Link the gate of TR2 to GND. Measure current consumption (VHF High Band 200mA ,UHF 400mA.) This can be adjust...
- Page 35 Technical Manual Installation and Operation This page left blank intentionally RELM/ BK RADIO...
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Page 36: Alignment And Testing
SMX920 Base Station & Repeater Technical Manual 7. Alignment and Testing The SMX920 test and alignment section assumes that the radio is a working module. Due to ongoing development the instructions may vary please refer to www.RELM.com for updates. 7.1 Transceiver Setup, Calibration and Alignment This section explains how to setup, calibrate and align the complete SMX920 Base Station. -
Page 37: Setting Ctcss/Dcs
The RSSI calibration is used to calibrate the RSSI meter on the in built menu system via Diagnostics Screen. The procedure requires an RF signal generator and the relevant leads to connect the signal generator to the RF input of the SMX920 Base Station. RSSI calibration is done via Calibration Screen. To complete the RSSI calibration, follow the instructions that in built menu system provides. -
Page 38: Tx Power Adjustment
SMX920 Base Station & Repeater Technical Manual 2060-ohm resistor between pins 4 and 6 of this connector of the SMX920 Base Station. Temperature calibration is done via the Calibration Screen. To complete the temperature calibration, follow the instructions that in built menu system provides. -
Page 39: Tx Centre Frequency Alignment
7.1.11 Microphone Line Input Level (Nominal Deviation Or Peak Deviation Mode) The required nominal deviation or Peak deviation is dependent on whether the radio is narrow or wide. The following table lists the required level for each case: RELM/ BK RADIO... -
Page 40: Mute Threshold Setting
SMX920 Base Station & Repeater Technical Manual Bandwidth FM Nominal FM Peak Deviation (kHz) Deviation (kHz) Narrow (12.5kHz spacing) Wide (25kHz spacing) Table 7-2 Nominal Deviation The radio is defaulted to work in this Nominal mode. The radio also can operate in a peak deviation mode. -
Page 41: Appendices
Technical Manual Installation and Operation 8. Appendices 8.1 SMX920 Interface Connections The user connections to the SMX920 are all made via the Front and rear panel where the following connectors are located. Conn Type Function Description N TYPE Simplex relay out or Location for internal simplex relay. -
Page 42: Cn6 Simplex Relay
SMX920 Base Station & Repeater Technical Manual 8.1.1 CN6 Simplex Relay This option maybe also pre-installed or retrofitted at a later date. The N type connector for the RX port is removed and the relay is mounted in it’s position, which then acts as the RF I/O port for simplex operation. -
Page 43: Establishing Rs232 Communications
SMX920. Wiring must be performed by the appropriate qualified personal, incorrectly wiring may cause damage to PC or SMX920. Please contact your Dealer or Distributor should you require the appropriate assistance. The following equipment will be needed to make this interface cable: ♦... -
Page 44: Software Menu System
Getting started with Hyper Terminal. 1. On the File menu, click New Connection. 2. In the Name box, type a name that describes the connection. (eg.SMX920) 3. In the Icon box, click the appropriate icon, and then click OK. 4. In the Connect To dialog box, select Com port you wish to use, and then click OK. -
Page 45: Interfacing Information
Consult RELM/BK Radio regarding current type approvals and for latest and current SMX920 Specification Data sheet. 8.4.1 Operating Frequency Bands The SMX920 is available in a number of models, which cover the range of operating frequency bands. Refer to Section 8.5 for details of the band breakdown. RELM/... -
Page 46: General
SMX920 Base Station & Repeater Technical Manual 8.4.2 General Parameter Specification SMX920 Rack Size: 3RU Tray, 330mm deep including fan. SMX920 Overall Physical Size 89mm high, 360mm deep, 483mm wide Weight < 9 kg Supply Voltage: 13.8V +/- 20%. Power Consumption: <400mA receive, typical 360mA. -
Page 47: Transmit
RF Switching Bandwidth PA: Full sub-band. Duty Cycle: 100% for 50W RF output with thermally controlled fan. RF Rise Time: < 10 mS with continuous VCO selected. < 200 mS with VCO in cold standby. Table 8-6 Transmit Specifications RELM/ BK RADIO... -
Page 48: Receive
SMX920 Base Station & Repeater Technical Manual 8.4.4 Receive Measured in accordance with TIA/EIA-603 standards. Parameter Specification Sensitivity: Better than –117 dBm for 12 dB SINAD. Typical –120 dBm. Selectivity 135-520MHz: More than 85 dB for 25 kHz adj channel. -
Page 49: Smx920 Model Number Configuration Guide
Installation and Operation 8.5 SMX920 Model Number Configuration Guide The SMX920 build can be specified by the model number. The diagram below shows how the model number is derived from the wanted options. Consult RELM Wireless Corporation for availability details on specific configurations and options. - Page 51 7100 Technology Drive West Melbourne, FL 32904 (800) 648-0947 Fax: (321) 984-0434 www.relm.com Ref. # 0300-30973-700 08-05...