CB uses either AM (like the commercial radio stations) or SSB (single side band-sounds kinda like Donald Duck if its not tuned correctly) on 27 Mhz.

The frequencies aren't the same, the mode of modulation is not the same; therefore they can't talk to each other.

Range of these radios is rather speculative. It's kinda like asking how for can you see? Looking out the window I can see the sun at something close to 93 million miles away, but if I walk into the closet and shut the door I can't see two inches. Except during unusual periods of atmospheric activity (and, well, ionospheric activity) these radios are going to be limited to what is called line of sight, and often times much less.

Trisha mentions the use of ham radio repeaters on the 146 MHz & 440 Mhz (what's wrong with 50 Mhz, 222 Mhz (my favorite), & 1.2 Ghz? <grin>), again you have to have line of sight to the repeaters in order to use them, but they effectively can extend your range, in some cases to over many thousands of square miles if you can get a signal to the repeater.

Cell phones are actually full duplex (gwad, more techno-babble: transmit and receive at the same time) repeaters, most on 800 Mhz. Again, you need to have line of sight to a cell site (cell tower).

I added all these frequencies to note that generally the higher the frequency, the more the radio frequency energy will be absorbed by things. What kind of things? Lotsa things: snow, wet vegetation, dry vegetation, rock, buildings, concrete, etc. Note that cell phones are at the highest frequency, but because of the abundance of cell sites this signal attenuation is not usually a major factor, until you go into the backcountry where fewer sites are to be found. The receiver needs a certain level of energy to hear the incoming signal.

Another factor in received signal strength is how much power you transmit. CB is 4 watts (or thereabouts, but its rare to find that in a portable radio), FRS uses 1/2 watt, cell phones use .6 watt (6/10 for those with eyes over 40 and miss the decimal point). Ham radio portables can sometimes run to the 7 or 8 watts, but the most popular is 5 watts. Antennas figure into the equation also. Portable ham radios can also use for more efficient antennas effectively doubling or quadrupling their power.

In my opinion nothing beats being prepared in terms of planning and equipment to be able to handle what is most likely to come up. But since we can't plan for all possibilities I recommend: 1) Cell phone because it takes no license and little skill, and the coverage is pretty fair. 2) Ham radio, excellent coverage, great flexibility, 3) FRS/CB are also rans. Not Rated) GMRS--cuz my experience is very limited.

As Trisha said getting a ham license is almost easy these days--no morse code, no diagrams, just some multiple guess questions. Pick up a copy of 'Now You're Talking' (at many Radio Shacks) or contract you're local ham club for more info.

Actually, I hope that Bonnie and I will be able to start caching again. Fire season is over (I think, Bon just told be about a smoke report on Lemmon, but isn't there snow up there?), our house is built, the barn is built, we're almost unpacked. I hope we will be able to run into some of you on the trail.