As a good rule of emergency management, if you can use your mobile phone use that option first!
Here is a hierarchy of methods to request help
1. Use your mobile phone to call 000 - if that doesn't work
2. Using your mobile phone, dial 112 - This will connect you to any telephone service provider that has a tower in your area and will connect you to the operator who will connect you to the 000 service. If that fails
3. Use a satellite phone that you have purchased or hired to dial 112 (this applies internationally).
4. Use your CB radio on Channel 5 UHF or Channel 9 HF. On a UHF try Duplex mode first, then try Simplex mode. On HF try AM mode first, then USB and LSB modes if the radio has these options. If you still get no response
5. Move to other channels on your radio. If you hear someone, transmit 'Mayday, Mayday, Mayday' (on any frequency) and if that station hears you, ask that they relay your request to the appropriate authority.
6. If you still can't get through to someone, move to a higher location and retry options 4 & 5.
7. Again, if that doesn't work, try to locate someone who can travel to the nearest populated area, or move within reception range of a mobile service or radio reception area.
8. If you have tried all these things, in cases of grave and imminent danger (ie a life threatening situation), activate an EPIRB beacon that you have bought or hired. This will transmit a signal that can be detected by satellite. The length of time it takes for responders to locate you, and the cost of the rescue will vary depending on your situation.
9. If you do not have an EPIRB, find a clearing, light a fire (or better still 3 fires, if possible to maintain that many fires) to attract attention. Place fires in a V pattern ( V is the international symbol for distress). Place sticks or other material in a V pattern near the fire. Make the V pattern big enough to see from the air. Do not keep moving your location, as it is much harder to find a person who is constantly relocating. If you are with a vehicle, stay with it, even if it has broken down.
Depending on where you purchased your sat-phone, and the country of origin of the sat service provider, you may be connected to the 000 service in Australia or another service such as 991 in America.
Always check with your provider before you need to make a call.
When everything else fails, radio communicatons continue...