Hi Pat (Patrick? Patricia? The Puppet Formerly Known as ‘Postman’? – Just kidding!),
Happy New Year!
Now, to answer your question, two-way radios use a range of what are called ‘frequency bands’ – these are areas of the electromagnetic spectrum (a fancy name for the total range of electromagnetic radiation) that are used for audio communication.
Most radios will operate on either VHF (Very High Frequency – any frequency range between 30MHz and 300MHz) or UHF (Ultra High Frequency – any radio frequency range between 300MHz and 3GHz) modes, but the two types of radio are incompatible with each other, so a careful choice is required on the part of the user.
Generally speaking, UHF radios are better suited to urban or indoor environments, whilst VHF has a slight advantage if you’re using your radio outside. For more on the VHF vs. UHF debate, check out Wendy from Stoke-On-Trent’s question, posted in December.
Anyway, the lowest frequency is the VHF Lowband frequency (25Mhz – 50MHz), whilst the VHF Highband frequency is anything between 126MHz – 174MHz. The general UHF Band is anything between 403MHz and 512MHz.
Of course, the right frequency for you depends greatly on your needs. Is your radio system used professionally or as a hobby? Is security an issue or not really? That sort of thing.
Remember also that it is illegal to use certain frequencies, as they are used by the Emergency Services. Two-way radio use is actually quite tightly monitored/restricted, largely for public safety purposes.
The course goes on to say that,
Anyway, is pays to do a little research before heading out into the field with your walkie talkie.