Realistic Patrolman PRO-3 VHF/UHF 3 Band Monitor Receiver

General Description

The PRO-3 Patrolman Receiver tunes three bands allocated by the FCC for service and business communications: VHF LO (30-50 MHz), VHF HI (152-174 MHz), and UHF (450-470 MHz). These bands are used for a variety of services including Fire, Police, Forestry, Conservation, Hospitals, Physicians, and Emergency Communications.

Designed for user utility, the PRO-3 is suitable for base station operation or mobile installation. It features SQUELCH, a narrow-band filter, and several-band operation. The unit is powered by either 12-15 VDC or 117 VAC 60 Hz and consumes minimal power, allowing over 200 hours of continuous operation from a single car battery.

The PRO-3 is an extremely sensitive receiver, comparable to a one-third microvolt signal. It includes a 10.7 MHz IF filter to reduce adjacent-channel or strong-signal interference, and a low-pass audio filter to improve readability of weak signals by reducing audio bandwidth.

The receiver is a complex circuit with 21 transistors, 9 diodes, and 2 thermistors, mounted in a steel chassis and cabinet. It is engineered for practical applications.

Guarantee: The REALISTIC guarantee is stated on the Fact Tag packed with the equipment, offering service from coast to coast with minimum delay.

General Specifications

• Tuning Ranges: VHF LO (30-50 MHz), VHF HI (152-174 MHz), UHF (450-470 MHz).
• Antenna Connections: 50-ohm coax for VHF LO/HI bands and UHF band.
• Sensitivity: 1 microvolt for 10 db S+N/N ratio.
• Selectivity: Filter out (15 KHz deviation), Filter in (5 KHz deviation).
• IF frequency: 10.7 MHz.
• Audio Output: 2 watts into 8 ohms (operates into 4-16 ohm loads).
• Solid-state Components: 21 transistors, 1 IC, 9 diodes, 2 thermistors.
• Power Input: 117 VAC 60 Hz or 12-15 VDC, negative ground only.

Note: Specifications are given in general form, emphasizing performance over numerical values.

Front Panel Controls: Identity and Locations

The front panel features:

• A: Illuminated slide-rule dial.
• B: Phones jack (2 watts low impedance audio).
• C: Volume control and power switch.
• D: Squelch control (eliminates no-signal noise).
• E: Selectivity switch (chooses broad or sharp characteristic).
• F: Band switch (LO, HI, UHF).
• G: Separate dial pointers for 30-50 MHz/450-470MHz and 152-174MHz.
• H: AF filter (improves weak signal readability).
• I: Tuning knob for 30-50MHz and 450-470MHz band.
• J: Tuning knob for 152-174MHz band.
• K: Knurled steel mounting screws.
• L: Steel mounting bracket.

How To Operate The PRO-3 Monitor Receiver

Installation: Ensure correct antenna connections and power source (12-15 VDC or 117 VAC). Set the AC/DC selector switch on the back panel appropriately. For DC operation, ensure correct polarity.

Initial Setup: Before turning on, set tuning controls to any position, VOLUME and SQUELCH controls fully counterclockwise, and AF FILTER to OUT.

Power On: Turn the VOLUME control clockwise. A click indicates power on. Gradually increase volume to a setting that provides a quiet hiss.

Tuning: Select the desired band using the band switch. Tune across the band for signals. Stations transmit intermittently, so multiple passes may be needed. Log station positions.

Squelch Control: Slowly advance the SQUELCH knob clockwise. The first setting eliminates receiver noise while allowing stations to be heard. A higher setting may cut out weak signals. If unsure, return the SQUELCH knob to its fully counterclockwise position.

Selectivity Control: Tune in a station with the SELECTIVITY control in the 15 KHz position. Then switch to the 5 KHz position. If the signal disappears, fine-tune the receiver. This sharp setting helps reject adjacent signals. It can also help with noisy signals of uncertain origin.

Table of FCC Listed Services Using VHF and UHF Bands

• Highway Maintenance Radio
• Forestry/Conservation
• Special Emergency
• Hospitals
• Ambulance and rescue
• Physicians and veterinarians
• Disaster relief
• Communications standby
• School buses
• Beach patrols
• Power Radio
• Petroleum Radio
• Forest Products
• Motion Picture
• Relay Press
• Special Industrial
• Business Radio
• Manufacturers Radio
• Telephone Maintenance
• Motor Carrier
• Railroad Radio
• Taxicab
• Automobile Emergency
• ESSA Weather Broadcasts (on 162.55 MHz and 163.275 MHz)

Rear Panel Inputs and Outputs: Identity and Locations

• A: Antenna connection for 450-470MHz band (UHF ANT).
• B: Antenna connection for 30-50MHz and 152-174MHz band (VHF ANT).
• C: Line cord storage brackets.
• D: For P.A. or Tape Input (TAPE OUT).
• E: Power Source Selector Switch (DC POWER AC).
• F: DC Power Connection Socket (DC12V +).
• G: AC Power Cord.

Cutting Instructions for Antennas

Radio Shack No. 20-177 Antenna (VHF HI 152-174 MHz / UHF 450-470 MHz): This is a quarter-wave (VHF) or five-eighths wave (UHF) vertical antenna for trunk lid mounting. The charts provide optimal lengths for efficient reception based on operating frequency and antenna length. Ensure all metal surfaces are clean and coated with water pump grease for reliability.

Radio Shack No. 20-176 Antenna (VHF HI 152-174 MHz / UHF 450-470 MHz): This is a wideband quarter-wave ground-plane antenna. The charts indicate cutting lengths for the whip and radials for specific frequency bands. For best performance, install the antenna at least ten vertical radiator lengths away from large metal objects.

UHF and VHF Antennas

Descriptions of available antennas:

• Dual Band Ground Plane: For outdoor use, 3 heavy-duty elements, 2-section vertical radiator, accepts PL-259.
• Indoor Hi-Lo Antenna: For indoor use, telescoping whip, terminates with pin-type plug.
• Dual Band Cowl-Mount: For mobile use, telescopic whip, swivel base, RG-58/U cable, terminates with pin-type plug.
• Omnidirectional Indoor Antenna: For indoor or portable use, plugs directly into receiver, 22" overall, decoupling skirt.

Model Pro-3 Block Diagram

The block diagram illustrates the signal path through the receiver, showing the VHF LO Front End, VHF HI Front End, UHF Converter, Wide Band Filter, Narrow-Band Crystal Filter, IF Stage and A.N.L., FM Detector, and Audio Output stages. It also shows the power supply and control circuits.

Model Pro-3 General Schematic

The general schematic provides a detailed circuit diagram of the PRO-3 receiver, including component values and connections for the various stages, power supply, and controls.

Schematic of VHF LO front end. 30-50 MHz.

Schematic of VHF HI front end. 152-174 MHz.

Schematic of UHF converter. 450-470 MHz.

Schematic of UHF converter buffer amplifier.

Other Realistic Patrolman Receivers

Radio Shack offers other Patrolman receivers, including the Pro-2 dual band (152-174 MHz and 30-50 MHz), the Pro-1 high band (152-174 MHz), and the Pro-1 low band (30-50 MHz). These models also offer base or mobile operation, FM or AM reception, and manual or crystal-option tuning.

Other Realistic Products Mentioned

• DX-150A: A professional receiver covering 535 KHz to 30 MHz, featuring FETs, mechanical filter, slide-rule dial, and solid-state components.
• TRC-23B: A 2-way 23-channel CB transceiver for base and mobile use, featuring dual IF system and automatic modulation level control.