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.
Some combination FRS/GMRS radios exist which may also have FRS channels 8-14. Such radios will be constrained to using a built-in antenna and will only transmit with 500 mW on those 7 channels.
Advantages:
Repeaters are permitted
High power limit on some channels
No limit on antenna gain
Can interoperate with FRS on some frequencies.
Generally supports CTCSS and sometimes DCS to keep radios quiet when other groups may be using the channel
Disadvantages:
License required
Radios may be expensive at times.
Mode: FM*
Antenna dimensions:
Quarter wave: 6"
Five eighths wave: 16"
Power:
Repeater inputs: 50 W
Interstitials: 5 W
RF Bandwidth: 25 kHz
Available channels:
Repeater: 8 pairs
Frequency listing (MHz):
Main group Repeater input 462.5500 467.5500 462.5750 467.5750 462.6000 467.6000 462.6250 467.6250 462.6500 467.6500 462.6750 467.6750 462.7000 467.7000 462.7250 467.7250
Main group may be used for simplex communications. Repeater inputs are for repeater operation only, with the repeater output being on the main group channel that is 5 MHz below it. The main group can be used to interoperate with FRS on channels 15-22.
Interstitial 462.5625 462.5875 462.6125 462.6375 462.6625 462.6875 462.7125
Interstitial channels are for simplex communications only. They can be used to interoperate with FRS on channels 1-7.
Backlinks: Communications:Two-Way Radio:Personal Radio Services