2 Way Radios

What is your intended application? Most 2-way radios won't be much use on a solo hike of interesting length, especially with interesting terrain, unless you're thinking of something bigger and heavier. You might be better off with a sat phone or other satellite communications device.

Or, for purely emergency use there are Personal Locator Beacons. About 4 ozs. $300 but no annual fee since the service is an international government one.
m.rei.com/product/815753/acr-electronics-resqlink-406-gps-personal-locator-beacon

The downside is it's strictly "life threatening". You push the button and the COSPAS-SARSAT satellite system activates and they launch a rescue. So there's no intermediate communication like with a SPOT or Inreach.



www.cospas-sarsat.int/en/

A Delorme InReach has both the SOS capability of a SPOT messenger as well as two way text messaging through satellite to either email or SMS text recipients. I've used mine a number of times this spring and summer and it has worked great. It was invaluable on a two-week, solo camping/hiking/road trip that I undertook in July and found myself having to make unexpected itinerary changes due to bad weather in remote areas with no cellular coverage. It can be paired with a cell phone through a bluetooth connection which allows it to be used in conjunction with Delorme's Eartmate mobile app. Text messages can be typed on the cellphone and sent through the InReach device and the Earthmate mapping capability essentially turns the InReach into a mapping GPS (whether or not it is good substitute for a mapping GPS I can't say since I've never used one.) The InReach will also function as a stand alone unit, though typing messages on it is more cumbersome this way and sending preset messages is preferred. I highly recommend looking into the InReach. I once, briefly, had a second generation SPOT messenger but returned it to REI. It would not transmit and SPOT customer service was subpar. SPOT uses a different- and, many say, inferior- satellite system than the InReach.

As others have mentioned, it really depends upon your intended use. There's only a narrow set of circumstances where a 2-way radio is very helpful, especially on solo trips, and it varies depending what frequencies you're using.

Walkie Talkies is what is usually mean't by two way radios, FRMS & GRMS , the later required getting a license (pay a fee)

www.amazon.com/Motorola-MH230R-23-Mile-22-Channel-Two-Way/dp/B001UE6MIO/ref=sr_1_1?s=electronics&ie=UTF8&qid=1441309568&sr=1-1&keywords=walkie+talkies

These might work if you were hiking with someone but were not together. But since they might not you would still need a plan for that , so for me they are not usually worth the bother.

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Ham Radio can often reach long distances, I have hit repeaters (like cell towers , but more often in mountains) from far away, usually you want to hit a nearby repeater to transmit to a much further place, some allow phone calls. There is one like that on Mt Hood. You need to bring a little book of repeaters or look them up before hand.
But sometimes I can't hit the repeater. Not sure if a ham hears me but does not pick up just to say hi, who would in an emergency. I think this is what the Park Service uses most places. The license for Ham Radio is a hard test - though I think I got 100% on the first part, and just pasted the 2nd part, in lieu of Morse COde. It also gets weather channel better than any other radio I have had, with a good antenna.

I now have a PLB but it is just good for emergencies (life threatening?). I have no experience with a spot etc. but I feel more confident about the PLB, and don't need to contact folks "at home" etc. Sat phone is expensive unless you get a deal (like those in Alaska?). I also have radio just for weather channels, which uses my flashlight batteries if needed, so it is small a very light but only take it on longer trips.

Those Motorla models you get at stores have miserable connectivity - used to take them on group hikes, but if there's lots of tree or ridges (and where aren't there trees or ridges in mountains???) that estimate of max distance goes away - a mile away and nothing but static.

When I was SAR we had high band radios that could use the occasional towers scattered through the Sierra - and, we had a portable antenna that one of us could hike up to a high place, and a plane that could circle high above to be a repeater. And still the connectivity was dicey. Teams were often left to fend for themselves and do the best they could if the search area was large. At least they worked better for teams that were within a few miles of each other than the commercial radios.

I have a Personal Locator Beacon and make sure my buddies always know where it (and the car keys) are in my pack, just in case I hit my head or am separated from my pack when incapacitated.