General Mobile Radio Service (GMRS)
Created Monday 26 December 2022
The General Mobile Radio Service (GMRS) is overall the most capable of the personal radio services. A license is required for legal operation. The license costs $35.
GMRS radios can interoperate with FRS radios, however, not all radios are capable of operating on all channels due to legal limitations.
Advantages:
Wide range of radio types available (Mobile, base, handheld)
Repeaters are permitted
High power limit on some channels
No limit on antenna gain
Can interoperate with FRS
Generally supports CTCSS and sometimes DCS to keep radios quiet when other groups may be using the channel
Repeaters are permitted
High power limit on some channels
No limit on antenna gain
Can interoperate with FRS
Generally supports CTCSS and sometimes DCS to keep radios quiet when other groups may be using the channel
Disadvantages:
Range may be especially limited in wooded areas due to UHF not passing through foliage easily.
License required
Radios may be expensive at times.
License required
Radios may be expensive at times.
Mode: FM*
*Technically many others are legal, but only FM is common.
Antenna dimensions:
Wavelength: 65cm
Quarter wave: 6"
Five eighths wave: 16"
Quarter wave: 6"
Five eighths wave: 16"
Power:
Main channels: 50 W TPO
Repeater inputs: 50 W TPO
Lower Interstitials: 5 W ERP
Upper interstitials: 500 mW ERP
Repeater inputs: 50 W TPO
Lower Interstitials: 5 W ERP
Upper interstitials: 500 mW ERP
RF Bandwidth:
Channels 1-7, 15-22: 25 kHz
Channels 8-14: 12.5 kHz
Channels 8-14: 12.5 kHz
Available channels:
Simplex: 22
Repeater: 8 pairs (overlapped with simplex)
Repeater: 8 pairs (overlapped with simplex)
Frequency listing (MHz):
Lower interstitial channels
Radio types: Mobile, Base, Handheld
Maximum power: 5 W ERP
Removable antennas permitted
Bandwidth: 25 kHz
Maximum power: 5 W ERP
Removable antennas permitted
Bandwidth: 25 kHz
Channel Frequency 1 462.5625 2 462.5875 3 462.6125 4 462.6375 5 462.6625 6 462.6875 7 462.7125
Upper interstitial channels
Radio types: Handheld
Maximum power: 500 mW ERP
Removable antennas prohibited
Bandwidth: 12.5 kHz
Maximum power: 500 mW ERP
Removable antennas prohibited
Bandwidth: 12.5 kHz
Channel Frequency 8 467.5625 9 467.5875 10 467.6125 11 467.6375 12 467.6625 13 467.6875 14 467.7125
Main group
Radio types: Mobile, Base, Handheld, Repeater
Maximum power: 50 W TPO
Removable antennas permitted
Bandwidth: 25 kHz
Maximum power: 50 W TPO
Removable antennas permitted
Bandwidth: 25 kHz
Channel Simplex Frequency Repeater input 15 462.5500 467.5500
16 462.5750 467.5750
17 462.6000 467.6000
18 462.6250 467.6250
19 462.6500 467.6500
20 462.6750 467.6750
21 462.7000 467.7000
22 462.7125 467.7125
Backlinks: Communications:Two-Way Radio:Personal Radio Services