® RITRON DR-145/445 PROGRAMMABLE FM RECEIVER MODULE MAINTENANCE & OPERATING MANUAL FOR USE ONLY BY AUTHORIZED SERVICE/MAINTENANCE PERSONNEL 0
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 4 4 6 7 7 7 7 DR-145/445 SPECIFICATIONS GENERAL RECEIVER 8 9 3. SETUP OPERATION INSTALATION 10 10 10 4. SUB-D 15 PIN CONNECTOR 10 5.
INTRODUCTION General RITRON's DR-145 and DR-445 resceiver module operates in one of a number of VHF or UHF frequency bands. Typical radio parameters such as frequency, squelch level and audio input and output gain are PC adjustable. The receiver is a single board unit with components on one side and pin for pin compatible with the DR-142/442. The unit supports voice through a microphone input and a nominal one watt speaker output or data through the auxiliary in and auxiliary out ports.
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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.
DR-145 SPECIFICATIONS GENERAL Frequency Range: O-band: 136 to 174 MHz RF Channels: 8 Independent RX frequencies Unusable 2.5 kHz RX steps in 136 to 174 MHz band: +/- 10 kHz around the 14.4 MHz harmonics at 144 MHz, 158.4 MHz and 172.8 MHz. Additional RX unusable 2.5 kHz steps RX 143.542 5 143.557 5 157.942 5 157.957 5 172.342 5 172.357 5 in 136 - 174 MHz band Frequency Stability: +/-2.
DR-145 SPECIFICATIONS Sensitivity (12 dB SINAD): RECEIVER 25 kHz Wide band 0.25 µV 12.5 kHz Narrow band 0.
DR-445 SPECIFICATIONS GENERAL Frequency Range: 400.6 – 416.5, 411 – 429, or 450 - 470 MHz RF Channels: 8 Independent TX/RX frequencies Frequencies unusable in 406.6 – 416.5 MHz band: None- all 6.25 kHz steps available RX 417.60000 418.03750 418.04375 418.05625 418.06250 Frequencies unusable in 411 - 429 MHz band Unusable 6.25 kHz steps: RX 460.80000 461.23750 461.24375 461.25625 461.26250 Frequencies unusable in 450 – 470 MHz band Unusable 6.25 kHz steps: Frequency Stability: +/-1.
RSSI squelch sensitivity: PC adjustable; factory set for –106 dBm Noise squelch sensitivity: PC adjustable; factory set for –121 dBm AUX OUT frequency response: AUX OUT level range: 12 - 2500 Hz @ +1 / -3 dB 0 to 3 Volts peak-to-peak Audio Speaker Output Audio Speaker freq response: >700 mW into 8 Ω, with less than 5 % THD ( 0 to 2.
SETUP OPERATION The DR-145/445 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.
Pin# 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 SUB D 15 PIN CONNECTOR The DR-145/445 is equiped with a 15 pin female sub D connector with the following functions: Function Least significant channel select bit (CS0) Channel select 1 (CS1) Most significant channel select (CS2) N/A N/A + 9 to 17 VDC input N/A Auxilary ouput PC programing port Volume control (RSSI option) Auxilary monitor input (pull to ground to open squelch). Can be used for tone detect, see below. Speaker output Carrier detect output (pulls to 3.
Speaker (pin 12) An 8 ohm or higher speaker should be connected to pin 12. One watt of audio power is possible. The speaker volume is set via the programmer AUX_OUT gain. The output signal can be further attenuated by a fixed or variable resistor from pin 10 to ground to attenuate the audio. Carrier Detect Output (pin 13) This line will be pulled to 3.3 volts through an internal 390 ohm resistor when a carrier is present. This output is carrier detect only.
PROGRAMMING THE RADIO PROGRAMMING THE RADIO USING A PC COMPUTER RITRON’s programming kit, DRL-PCPK-2.2, allows programming of the DR-445 model radios using a PC compatible computer. The PC Programming Kit Includes: 1) Ritron Transceiver programming software, DRL-PCPS-2.2, which is contained on a CD-ROM. 2) Ritron PC to radio adapter cable, 9/RTC-PAS, which is terminated at one end with a DB-25F connector, at the other end with a 6 pin modular plug.
DR-145/445 THEORY OF OPERATION POWER SUPPLY AND VOLTAGE DISTRIBUTION The DR-145/445 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.
Two types of squelch circuits exist, an RSSI squelch and a NOISE squelch. Both types can be used simultaneously or either one or the other can be used. The RSSI (receive signal strength indicator) squelch, which is typically set around –108 dBm, must be set to open at a higher level than the noise squelch. This is necessary since the RSSI measures total power in the receiver IF bandpass. All background noise, which at VHF can be high, is seen as signal.
MICROCONTROLLER The DR-145/445 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. DESCRIPTION Input is pulled LOW when the PTT input is grounded to initiate transmitter operation. Input is pulled low when high/low power input is grounded.
DR-145/445 ALIGNMENT PROCEDURE Only an authorized RF service technician should perform test and alignment of the DR-145/445. The unit is PC adjusted.
