DTX-145M Rev.
TABLE OF CONTENTS SECTION TOPIC 1. INTRODUCTION GENERAL Model Identification FCC REGULATIONS Licensing Exposure to Radio Frequency Energy FCC Label MAINTENANCE INFORMATION Surface Mount Repairs Precautions for handling CMOS Synthesizer shield 2. PAGE 2 2 4 4 6 7 7 7 7 DTX-145M SPECIFICATIONS GENERAL RECEIVER TRANSMITTER 8 9 9 3. SETUP OPERATION INSTALATION 10 10 10 4. SUB-D 15 PIN CONNECTOR 10 5.
INTRODUCTION General RITRON's DTX-145M transceiver module operates on one of 5 frequencies in the license free VHF band. Typical radio parameters such as frequency, power, deviation, deviation balance, squelch level and audio input and output gain are PC adjustable and have been set up at the factory for typical operation. The transceiver is a single board unit with components on one side and pin for pin compatible with the DTX-145.
DTX-145M-BE Enclosed version 3
FCC REGULATIONS Licensing The FCC requires the radio operator to obtain a station license for the radios before using them to transmit, but does not require an operating license or permit. The station licensee is responsible for ensuring that transmitter power, frequency and deviation are within the limits specified by the station license. The station licensee is also responsible for proper operation and maintenance of the radio equipment.
Compliance with RF Exposure Standards Your Ritron two-way radio is designed and tested to comply with a number of national and international standards and guidelines (listed below) regarding human exposure to radio frequency electromagnetic energy. This radio complies with the IEEE and ICNIRP exposure limits for occupational/controlled RF exposure environment at duty factors of up to 50% talk and 50% listen and is authorized by the FCC for occupational use.
Antennas • Install vertical omni directional antennas above a suitable ground plane taking into account the recommended minimum lateral distances in table 1. The antenna installation should additionally be in accordance with: a.) The requirements of the antenna manufacturer/supplier. b.) Instructions in the Radio Installation Manual, including minimum antenna cable lengths. c.
MAINTENANCE INFORMATION Surface Mount Repair RITRON surface mount products require special equipment and servicing techniques. Improper servicing techniques can cause permanent damage to the printed circuit board and/or components, which is not covered by RITRON’s warranty. If you are not completely familiar with surface mounted component repair techniques, RITRON recommends that you defer repair to qualified service personnel.
DTX-145MSPECIFICATIONS GENERAL FCC ID: AIERIT17-145M FCC Rule Parts: 95J Frequency Range: 5 MURS channels RF Channel selection: Via pins1, 2 and 3 Frequency Stability: +/-2.5 PPM (-30 to +60 C) Tone/Code Signaling: CTCSS (Quiet Call) and DCS Power Supply: 9 to 17 VDC Current Drain: RX Standby: 25 mA at 12.5 VDC Dimensions & weight: Board only version: Shielded version: Encased version: 4.75” x 2.8”x .625” 2.1 oz 4.75” x 2.8”x .625” 3.4 oz. 5.7” x 3” x 1.375” 7.3 oz.
DTX-145MSPECIFICATIONS Sensitivity (12 dB SINAD): RECEIVER 25 kHz Wide band 0.25 µV 12.5 kHz Narrow band 0.
SETUP OPERATION The DTX-145M uses two connectors for operation and one for factory use. The sub D-15 contains signal, control and power lines and the RF connector receives low level signals and transmits power. The third connector on the unit is used for initial factory flash programming of the unit. The radio’s eight transmit and receive frequencies are programmed via a PC. Pins 1, 2 and 3 of the DB-15 connector select the channel.
SUB D-15 PIN CONNECTOR The DTX-145M is equiped with a 15 pin female sub D connector with the following functions: Pin# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Function Least significant channel select bit (CS0) Channel select 1 (CS1) Most significant channel select (CS2) Microphone input High/ low power select (pull low to get low power) + 9 to 17 VDC input Auxilary input Auxilary ouput PC programing port Volume control (RSSI option) Auxilary monitor input (pull to ground to open squelch).
Connecting a 10K pot to ground at this point will allow the speaker volume to be adjusted. For maximum range the internal AUX_OUT gain should be set to a value that allows maximum volume with acceptable distortion when the pot is set at 10K. Optionally, this pin can be used as an RSSI output. If desired, contact the factory. Monitor Input (pin 11) Normally the AUX_OUT and SPEAKER_ OUT are switched on only when a carrier with required tone, if programmed, is detected.
PROGRAMMING THE RADIO PROGRAMMING THE RADIO USING A PC COMPUTER RITRON’s programming kit, DTXL-PCPK-2.4 or DTXL-PCPK-2.4-USB, allows programming of the DTX-145M model radios using a PC compatible computer. The PC Programming Kit Includes: 1) Ritron Transceiver programming software, DTXL-PCPS, which is contained on a CD-ROM. 2) Ritron PC to radio adapter cable, 9/RTC-PAS or 9/USB-PAS, which is terminated at one end with a DB-25F or USB connector, at the other end with a 6 pin modular plug.
DTX-145M THEORY OF OPERATION POWER SUPPLY AND VOLTAGE DISTRIBUTION The DTX-145M is powered by a 9 to 17 VDC external power supply. F601 is a 3A reset able fuse in series with J301 for short circuit or reverse connection protection. If reverse voltage is applied, F601 will temporarily “blow” open when excess current flows through D601. Disconnect the supply to reset the fuse. Reconnect power correctly and proceed. An input voltage below 17 VDC must be maintained.
detects the FM IF signal. One input of the quadrature detector is connected internally to the IF signal from pin 11 while the other input is the phase-shifted signal from Y102 at Pin 10. Demodulated audio appears at Pin 9, where a lowpass filter formed around U303-C removes the spurious second IF output prior to application to the voice, tone and squelch conditioning audio circuitry. Two types of squelch circuits exist, an RSSI squelch and a NOISE squelch.
RF Path and control The VCO feeds pre-driver stages Q402 and Q404 which feeds the pre-driver Q203 and driver Q202. The final Q201 is an FET device. The power supply to the Final power FET Q201 is turned on by a voltage regulator built around Q209. The power supply to the driver is controlled by a feedback power controller. The power control circuitry maintains a constant current supply to the final Q201 transistor. Q208 is monitoring current through the two paralleled 0.1 ohm shunt resistors.
MICROCONTROLLER The DTX-145M transceiver is electronically controlled by U301, an 8-bit flash programmable microcontroller. U301 has A/D inputs and PWM outputs for processing analog signals. Radio characteristics are stored in internal EE memory. Its RS232 port is used in programming the radio’s personal characteristics such as frequencies and tones. PIN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 DESCRIPTION Input is pulled LOW when the PTT input is grounded to initiate transmitter operation.
DTX-145M ALIGNMENT PROCEDURE Only an authorized RF service technician should perform test and alignment of the DTX-145M. The unit is PC adjusted. RECOMMENDED TEST EQUIPMENT 1) 12.
19) Remember to save all settings when tuning is finished. NOTES: *Sub audible tone deviation is automatically set to be within 600 to 900 Hz after this adjustment on wide band channels. Maximum voice and tone deviation on wide band channels will then be 4800 to 5300 Hz. Narrow band tone deviation will be 350 to 500 Hz with overall deviation of 2400 to 2650 Hz. **The DTX-145M is capable of two squelch operating modes. Both can operate simultaneously. See the FM Receiver Subsystem section for theory.
