In the US for ELT's my understanding is that the AFRCC will wait for at least three sat passes to enable them to get a decent fix on the location. That means about 3 to 4 hours, the notice will then go to the designated SAR group for that area. In Pennsylvania it is usally about 5 hours after first signal is recieved before the notice goes to the local SAR personal figure about 30 to 60 minutes for an aircraft to be lanched and a UDF team to get into the search area then the real work starts assuming that the signal is accuired by the aircraft and it guides the UDF team to the location best case it would be about 6 to 8 hours before the team would arrive at the beacon's location. It's the last half mile that's the hardest. Please note that most becons do not work well in heavy woodland, I have seen beacons that we could not recieve on the ground from more than 100 Yards but the aircraft could here it from several miles away. Rember the more sky you can see the better chance the you will be heard.