Note
GR-1131 1976-1977 $89.95 (high)
GR-1132 1976-1979 $139.95 (lo/high/uhf)
GR-1133 never sold (aircraft band)
MR-1134 1976-1977 $99.95 (high)
Released for Christmas in 1976. Heath replaced the GR-110 with the GR-113X series of scanning receivers. The GR-113X series is more conventional in appearance than the GR-110 in that the channel display is a row of lights that scan from left to right with push buttons under each light that lock each channel in or out.
Heath designed four versions of the scanner, but only three were actually sold, and two of those were identical. The scanners differ from each other only by the presence or absence of three small front end PC boards, one each for the low, high, and UHF frequency bands. The IF and scanner circuit boards are the same for all versions.
The 113X priority channel is channel 1 and is sampled every 4 seconds when it is selected. The radios feature a scan resume delay of about a half a second that is not adjustable or defeatable.
The GR-1131 and MR-1134 are VHF high band units covering any 8 MHz band segment from 146-174 MHz. They appear to be identical (except for the color of the front panel and cabinet), but were marketed in separate parts of the catalog to separate interest groups—the MR-1134 was sold as a marine channel scanner.
The GR-1132 is a LO/HI/UHF unit. It covers any 10 MHz segment from 30 to 50 MHz, any 8 MHz segment from 146 to 174 MHz, and any 8 MHz segment from 450 to 500 MHz.
The GR-1133 was to be an aircraft band scanner. Although it was advertised in the ’77 Christmas catalog as being available in January ’78 the GR-1133 never materialized.
All versions have a rated sensitivity of better than .5 µV for 12 db SINAD, and all use a 10.7 MHz IF with a 4 pole crystal filter. An 8 pole filter was available as an option. Refer to photo for the location of the optional filter parts.
The GR-1132 has three separate built-in antennas while the other units have only one. All versions have external antenna jacks on rear panel and versions feature a built-in speaker but make no provision for external speaker. All use PC board construction and are designed for 120 VAC, 50/60 Hz, or 12 VDC operation and come with an AC cable. For DC operation Heath supplied only a plug—you had to make your own cable.
Some units may make a faint ticking sound while scanning and some units may make a distinct “pop” each time the priority channel is sampled. The popping sound is a little irritating but can be eliminated by turning off the priority channel.
The kits were originally supplied with an alignment generator—a small circuit board assembled by the customer—with several wire leads, an integrated RCA plug, an RF level control and a small incandescent lamp. This generator takes power from the scanner to provided a 10.7 MHz signal used to align the IF board, and an on-channel signal used to align the RF stages. The lamp is used as a level indicator. Because these generators are virtually never found with the scanners today, the schematic in included here should the reader wish to construct one. Refer to photo.
The GR-113X radios have brown wood-grain metal cabinets, and brown or gray front panels. The MR-1134 has a beige cabinet and a green front panel. Even though they worked OK, no one was real impressed with these scanners, and in the end, Heath eliminated them with big price reductions.
The assembly manual will be required for alignment.
The following specifications apply to specifically the GR-1132, but also generally to the other versions of the scanner.
CRYSTAL FREQUENCY CALCULATIONS
VHF LO: channel frequency + 10.7 MHz
VHF HI: (channel frequency - 10.7) / 3
450-470 MHz: (channel frequency - 10.7 ) / 9
470-500 MHz: (channel frequency - 10.7) / 10
Frequency range:
LO VHF 30 to 50 MHz
HI VHF 147 to 174 MHz
UHF 450 to 500 MHz
Scanning range:
LO VHF any 10 MHz segment of the range
HI VHF any 8 MHz segment of the range
UHF any 8 MHz segment of the range
Sensitivity (of aligned channel):
LO VHF 0.5 µV or less for 12 db SINAD
HI VHF 0.5 µV or less for 12 db SINAD
UHF 0.7 µV or less for 12 db SINAD
Modulation acceptance: ±6.5 kHz minimum
Antenna input impedance: 50 Ω
Channels: 8, crystal controlled
Adjacent channel rejection: –40 db typical, (±30 kHz channel spacing)
–55 db typical with optional 8-pole filter
Scan rate: about 16 channels per second
Scan delay: about 0.5 seconds
Priority channel scan interval: about every 4 seconds
IF: 10.7 MHz
Audio output:
AC operation: 1 watt with 10% or less distortion
DC operation: 2 watts with 10% or less distortion
Power requirements:
AC operation: 120 VAC, 60 Hz, 12 watts
DC operation: 13.8 VDC, 300 mA squelched, 500 mA at full audio
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.
