VHF FM DIGITAL TRANSCEIVER ST-3118C (400Mhz ~ 470Mhz) SERVICE MANUAL SmarTrunk Systems, INC. ST-3118C SM R1.
Contents 1. Specifications: ............................................................................................................................... 5 2. ST-3118 EXPLODED VIEW.............................................................................................................. 6 3. ST-3118C SIMPLIFIED DIAGRAM ................................................................................................... 7 4. - ST-3118 RF DESCRIPTION ..................................................
5.6.2.1. High POWER LEVEL ALIGNMENT..................................................................................... 16 5.6.2.2. Mid POWER LEVEL ALIGNMENT...................................................................................... 17 5.6.2.3. LOW POWER LEVEL ALIGNMENT .................................................................................... 17 5.6.3. ANALOG MAXIMUM DEVIATION ........................................................................................ 17 5.6.4.
9. ST-3118 FRONT BOARD SCHEMATIC............................................................................................... 33 10. COMPONENT LOCATOR .................................................................................................................. 34 10.1. ST-3118C COMPONENT LOCATOR (TOP LAYER) ......................................................................... 34 10.2. ST-3118C COMPONENT LOCATOR (BOTTOM LAYER) ................................................................
4. - ST-3118 RF DESCRIPTION 4.1. Circuit Configuration LPF The receiver is a single receiver with built DSP fully integrated. Incoming signals from the antenna, after passing through LPF filter, are fed direct to the DSP down converter to get the baseband voice from 0Hz to 3500Hz. Demodulated signals are filtered and conditioned onto a second DSP based filter, which also includes a high efficiency 4FSK modem.
analyzes the expected signaling programmed on the current channel table. In case of not any additional signaling must be decoded, or the signal has been detected, the main processor (U13) asks to the audio processor (U12) to open the audio path, unmuting the audio amplifier (U8). 4.2.4. Virtual VOLUME CONTROL The potentiometer position (R15 – front board) is measured by one analog to digital converter on the audio processor (U12), and then the information is reported to the main processor.
and fed it to the audio power amplifier (U8). corresponding balance controlled by software. Mic External Internal PW Mic Selec tor [U5] AMP LIFIE R VOCO DER [u14] AUDI O PROC ESSOR VC TXCO [Y1] MAIN PROC ESSOR [U13] TRANSM ITTER [U2] Figure 4: Digital Modulation path 4.3. Transmitter System 4.3.2. DIGITAL TX AUDIO: 4.3.1.
7141). The reference power level are TX CTRL [Q9 Q18] LPF Ant Sw D1/D2/ D6 Power Detection U1 Final AMP U3 Driver Q2 Buffer AMP Q1 POWER CTRL [U10] Figure 6: RF transmission path 4.3.3. Drive and Final Amplifier Stages Final RF is amplified on Q1 (2SC5226) adjusting the impedance, then filtered to be fed to Q2 (2SC3357) then finally amplified by U3 (RA60H1317) up to 50 watts output power.
5. ST-3118 ALIGNMENT 5.1. Introduction The ST-3118 series is carefully aligned at the factory for the specified performance across the frequency range depending for each version. Realignment should therefore not be necessary except in the event of a component failure, or altering version type. All component replacement and service should be performed only by an authorized SmarTrunk representative, or the warranty policy may be void.
is clearly isolated electrically from all other steps. Have all test equipment ready before beginning, and follow all of the steps in a section in the order presented. 5.3. Required Test Equipment RF Signal Generator with calibrated output level at 1 GHz Deviation Meter (linear detector) In-line Wattmeter with 5 % accuracy at 1 GHz 50 Ohm RF Dummy Load with power rating 10W at 1 GHz 8 Ohm AF Dummy Load (Attention: Audio output is BTL output) Regulated DC Power Supply (standard 13.
Please be sure you turn the radio on before continue with this alignment procedure. 5.5. MAIN RADIO ALIGNMENT Before setup any parameter, run SDR programming software then select Radio Alignment from top bar menu. As soon as the radio is detected, actual radio parameters are loaded. Once the radio is connected, a new screen pops up showing all alignment parameters.
Setup the test equipment as shown for transceiver alignment, apply 13.8V DC power to the transceiver. The RF parameters are typed on the alignment software to facilitate the alignment within all radio band avoiding special programming of the radio before start alignment procedure. All parameters can be aligned without relationship to any other, so there is no an order to align. On this way, you can adjust only the desired parameter, avoiding to waste time realigning other parameters than required.
For power alignment, you can do a fine-tuning as per your desire frequency sub-band. The software lets you linearize the complete band dividing the complete band into five steps to let you focus into your frequency bands. Even when the software has already assigned the most convenient frequency points to consider the alignment, you still can enter exactly the frequency of your interest. 5.6.2.1. High POWER LEVEL ALIGNMENT To align the High Power level select Power High Level.
5.6.2.2. Mid POWER LEVEL ALIGNMENT Repeat the same procedure to align High Power, but select Max Deviation alignment option alignment menu. form the Power Medium Level on the alignment menu. Figure 15: Analog Max Deviation Alignment Actual alignment value will be displayed on alignment slider. Figure 13: Medium Power Level Alignment 5.6.2.3. LOW POWER LEVEL ALIGNMENT Repeat the same procedure to align High Power, but select Power Low Level on the alignment menu.
5.6.4. Modulation Gain alignment: This is a critical parameter, which may not be realigned to different values other than factory default. Lower gain means a very high microphone gain must be assigned to get the proper radio voice deviation, and higher gain means a risk because the max deviation limit must be reached by any signal, which makes the limiter to introduce distortion to avoid over deviation. As soon the desired value is reached, press [Finish] to store the value on radio memory.
As soon the desired value is reached, press [Finish] to store the value on radio memory. As soon the desired value is reached, press [Finish] to store the value on radio memory. If you want to retrieve factory default, press [Factory] instead of [Start]. You will be asked to confirm the factory default alignment, and then if you confirm it, original values from factory will be loaded into current alignment settings. Default value corresponds to 2.2 KHz deviation for Narrowband channels (12.
reference proposes. tone for alignment As soon the desired value is reached, press [Finish] to store the value on radio memory. Default value correspond to 1.8Khz deviation for narrow band channels. If you want to retrieve factory default, press [Factory] instead of [Start]. You will be asked to confirm the factory default alignment, and then if you confirm it, original values from factory will be loaded into current alignment settings. 5.6.8.
Press Start then move the slider to reach the desired value at the time you checks the deviation meter to reach the desired signaling level for narrow band operation. Radio will generate 134.4Hz audio tone for alignment proposes. Press [Start] then move the slider to reach the desired value at the time you checks the deviation meter to reach the desired signaling level for narrow band operation. Radio will generate 123.0Hz audio tone for alignment proposes.
Press [Start] then move the slider to reach the desired value at the time you checks the deviation meter to reach the desired signaling level for narrow band operation. Radio will generate a 1000Hz alignment reference tone for alignment proposes. As soon the desired value is reached, press [Finish] to store the value on radio memory. Default value corresponds to 1.8 KHz deviation for narrow band channels (12.5Khz channel bandwidth).
5.7. RECEIVER ALIGNMENT Setup the test equipment as shown for Receiver alignment, apply 13.8 V DC power to the transceiver. The RF frequency must be loaded on Receiver Frequency of the alignment software to facilitate the alignment within all radio band avoiding special programming of the radio before start alignment procedure. RF signal generator Figure 25: Discriminator Gain Alignment Screen Actual alignment value will be displayed on alignment slider.
6. COMPLIMENTARY USER ALIGNMENT The above parameters only can be aligned under dealer login and most of them should be critical for proper radio performance. Additional complimentary parameters should be also aligned on user login mode; it means the user can align it as per the most convenient way for particular radio usage. 6.1.
6.1.2. ANALOG External Mic Gain: It aligns external microphone Accessory Port) sensitivity. Default factory value is 0.0dB. For example, if you want a dynamic gain which causes the same effect that a gain of 6.4dB when the voice on the microphone causes 50mV RMS in the microphone switch output (standard voice at 4 inches away from the microphone), or 0dB gain on the external microphone connection, then you must program the Analog Gain at 6.
gain on the Mic Gain then check the Digital ACG Check Box. For example, if you want a dynamic gain which causes the same effect that a gain of 15.0dB when the voice on the microphone causes 50mV RMS in the microphone switch output (standard voice at 4 inches away from the microphone), or 6.0dB gain on the external microphone connection, then you must program the Digital Gain at 15.0dB and the external gain on 6.0dB, then check Digital AGC as bellow: 6.1.6.
6.1.7. DISABLE RF POWER Use this box to check when you do not want to use the RF power amplifier. It is commonly used for dealers to make a demonstration of the radio features without interfering to any other existing user in the frequency or for operation without antenna connected to the radio. To disable the RF power amplifier, check the box: Press [OK] to store it in the file. The value will be updated after the file is transferred to the radio. ST-3118C SM R 1.1 SMARTRUNK SYSTEMS, INC.
7. RADIO APPEARANCE ALIGNMENT Under user mode, login appearance can be aligned. radio Select Edit then appearance from radio top toolbars to access to the appearance screen: 7.1.1. Auto backlight delay alignment: The auto backlight mode, automatically set on power off status to the backlight, after any event, to reduce the battery demand. To change the value of the delay before the backlight is powered off; please enter the quantity of desired seconds for it.
Second folder on appearance screen allows the user to adjust the tones, which are played back in any event. will play back any annunciation message for some important events, as per the associated check box. Voice and language of annunciation events can adjusted as per user request. the be Figure 35: Courtesy Tones Programming Screen Tones can be changed by the dealer. Please refer to appendix II to learn about it.
status: Powered on, Powered Off, Fix, etc. Check RSSI if you want the radio plays a concerning message back any time you ask for current RSSI. Press OK once you finish setting all desired messages. This feature will be stored into the file then it will be transferred to the radio at the time the file is uploaded to the radio. ST-3118C SM R 1.1 SMARTRUNK SYSTEMS, INC.
Notes: ST-3118C SM R 1.1 SMARTRUNK SYSTEMS, INC.
Copyright 2014 Printed in Malaysia www.smartrunk.com ST-3118C SM R1.
FCC Notices FEDERAL COMMUNICATIONS COMMISSION INTERFERENCE STATEMENT This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation.
