As a licensed radio service, GMRS, the General Mobile Radio Service, operates in the 462 and 467MHz range. Most people that use GMRS, not all, but mostly GMRS is used in groups. As a radio standard, any GMRS radio can talk to any other GMRS radio. If you get a group of people, or just two people who want to talk to each other, GMRS would be a good choice: no test, low license fee, easy operate, clear voice.
If you already take a GMRS handheld radio, this may happen to you a lot. You may hear people talking on say CH16, but every time you try to talk to them, no one reply. They’re not ignoring you, the truth is that they can’t hear you. You can’t talk to them unless you configure your radio to use one of those special repeater channels, and set it all up.
GMRS is limited to 22 channels plus 8 more special repeater channels. For example, this is the frequency chart of UV-5G. You can see that CH1-CH22 are standard channels, and CH23-30 are repeater channels.
Many radios have channels that you can configure to use as repeater channels, but you’re limited to only those special eight repeater channels all the time. Some GMRS radios have extended DIY repeater channels, CH31-CH54 except for the common CH23-CH30. Such as our BAOFENG UV-9G and G11S. You would get a total of 4 groups of repeating frequencies to set different CTCSS/DCS and reduce the interruptions. If your GMRS radio is repeater capable, you can set up to use special channels 23 through 30 to talk on a repeater.
Repeater channels share and overlap with the regular 22 GMRS channels, this may cause much confusion. What is the difference between repeater channels and simplex channels (what we call regular channels)? Don’t know what needs to be set up to talk through a repeater? Then let’s quickly go over some of the definitions.
Simplex means talking directly from radio to radio, from walkie-talkie to walkie-talkie. Just pick up your radio, press the PTT button, and talk to your friends on your walkie-talkie, direct radio to radio communication. This is called the simplex GMRS channel. You don’t have to worry about frequencies because they're pre-programmed well in every channel.
GMRS repeater channels are different than the simplex channels. The main difference is that a repeater channel is two channels combined to frequencies, combined on a GMRS radio. There are two channels or two frequencies that transmit and receive when you’re using one of the repeater channels. The radio automatically transmits on one frequency and receives on another frequency. This is how the repeater works. When you're talking with your friend, all your GMRS radios using that repeater channel are transmitting out on one frequency. Then you can talk to each other in the further range.