Note
The Icom IC-R72 is an HF communications receiver designed for both desktop and mobile applications. It utilizes a twin CPU control system for streamlined operation.
It was introduced in 1990 as the successor to the IC-R71 series, moving toward a more streamlined design with fewer front-panel controls and a simplified interface. During its production run, it served as a mid-range tabletop receiver until it was eventually succeeded by the IC-R75 in 1999.
The R-72 was available in three power related hardward configurations.
1. AC/DC Type (Desktop)
This was the standard home-use version. It included an internal AC transformer and was supplied with a region-specific AC power cable. While primarily for AC, it also included a 13.8V DC jack.
2. DC Type (Mobile/Portable) Instead of an AC transformer, it was supplied with the OPC-131 DC power cable. AC Compatibility: It could be used with a standard wall outlet by using the optional AD-55 AC adapter.
3. Battery Type (Self-Contained Portable)
This could be either the AC/DC version, or the DC-only version. It came from the factory with a lead-acid battery and a required an internal jumper. The battery would run the receiver for about one hour, and was designed less for portable operation and more as a backup to carry you through a power AC power failure. This model featured a specific 2A fuse for its internal regulator circuit, which was not standard on the other types.
User installable options include:
– UI-8 FM Unit: Adds wide-band FM reception capability.
– UT-36 Voice Synthesizer Unit: Provides an audible announcement of the displayed frequency in English when the "Speech" button is pressed.
– CR-64 High-Stability Crystal Unit: Replaces the standard crystal for improved frequency stability.
– Optional IF Filters: The receiver can accommodate specialized narrow filters for improved selectivity in CW or RTTY modes.
Features
– Operating Modes: Supports SSB (USB and LSB), AM/N, and CW/N as standard. Wide-band FM reception is available with the installation of the optional UI-8 FM unit.
– Memory and Tuning: 99 Memory Channels: Allows for the storage of frequency and mode data across 99 channels.
– Direct Keypad Entry: Features a front-panel 10-key pad for immediate frequency, memory, or time input.
– Selectable Tuning Rates: Frequency can be adjusted in either MHz or kHz steps for rapid or fine tuning.
– Main Dial Lock: Includes an electronic dial lock to prevent accidental frequency changes.
– Signal Processing and Enhancement:
– Built-in Preamplifier: Operates at 1.6 MHz and above to improve sensitivity for weak signals.
– Dual-Level Attenuators: Features 10 dB and 20 dB attenuators to manage strong interfering signals.
– Advanced Noise Blanker: Includes a standard noise blanker and a "High" level setting specifically for heavy pulse noise.
– Adjustable AGC: Allows the user to change the time constant of the Automatic Gain Control circuit.
– Clock and Timer Functions:
Dual Clock: Displays two independent times.
Timer System: Features a power-on timer and a sleep timer for automated operation.
– Interface and Customization:
– Computer Control: Equipped with a CI-V remote control jack for connection to a personal computer via an optional level converter.
– Tape Recorder Support: Includes dedicated jacks for audio output and remote start/stop control of a tape recorder.
– Optional Voice Synthesizer: Can announce the displayed frequency in English when the optional UT-36 unit is installed.
– Antenna Connections:
50 Ω: Uses a PL-259 coaxial connector.
500 Ω: Includes a push-terminal for long-wire antennas and a dedicated ground terminal.
– Audio Output: Internal/External Speaker: Provides audio through an internal speaker or a rear-panel external speaker jack.
– Headphones: Features a front-panel standard headphone jack that mutes the internal speaker when in use.
– Operating Temperature Range: Guaranteed performance between −10∘C and +60∘C (+14∘F to +140∘F).
Power Supply Requirements:
DC Operation: 13.8 V DC ±15%.
AC Operation: Internal power supply compatible with various global voltages (100–120V or 220–240V depending on the version).
