(2m, 70cm, 10m, 11m) These are all frequency bands specified by their average wavelengths (frequency = 1/wavelength). Different radios/antennas are needed to communicate within each of those frequencies, although multi-band radios do exist. 2m and 70cm are the most common amateur (ham) radio frequency bands used for general communication off-road, at least in the US. Within each of these bands exist regions designated for amateur radio uses as well as those designated for other users. Knowledge of this is one of the many reasons amateur radio requires a license.
CB - Citizen's Band Radio, is a group of radio frequencies within the 11m band that can be used by anyone without a license, but radios are more limited in power than amateur radio.
SSB - Single Side Band - essentially a type of signal encoding, in reality for users of radios this doesn't matter (most radios pre-select the type of signal for the frequency you set), but will affect the ability of a signal to propagate and penetrate through noise.
Clear as mud?
Amateur radio allows more power and use of a broader range of frequencies which increase your ability to be heard father away, which also translates into clarity over the radio. As you learn more about radios, you'll learn when certain bands are more useful, but in the end for most of our uses it depends on who we can expect to be listening.
CB radio may be more prevalent in your area, but has more power restrictions making it less than ideal from a signal propagation standpoint. Basic CB radios are also typically cheaper than basic Amateur radios.
It's a trade off in terms of money, clarity, and usage patterns of others in your area. i.e. If everyone else on your trail has a CB, an amateur radio doesn't get you much even if it sounds better.
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