Modern Beacons such as the HR Smith CPI have a GPS locator signal embedded in the transmission signal. It is actually possible to locate a beacon with little in the way of technical equipment as was proved a several years ago.
A beacon was inadvertantly deployed and landed in a field of standing wheat.
The satellite fix probably gave a search area of about a square mile.
The only location equipment available was a hand held tranceiver tuned to 121.5.
By listening to the signal strength they were able to cut the search area to a couple of hundred square yards. They then retracted the aerial to detune the transceiver further.
They eventually reached a point where they could not determine a direction, looked down and there it was!!!!
Sounds simple, on a hot summers day it was a great effort tramping around the fields and much applauded.
I suspect that weather in the search area and difficult terrain are generally more of a problem than the signals themselves.