All aircraft communications is done with VHF-AM signals. Miltary aircaft run on UHF-AM with their emergency frequencey of 243 Mhz. SARSAT is monitoring 121.5 as do many comercial aircraft. Light aircraft do not normaly monitor 121.5 but may be found on a local unicom frequencey. Most VOR's and towers monitor 121.5. If your are involved in an emergency 123.1 is set aside for SAR communications. If a ground SAR team is comming for you and they have DF equipment they will be able to hear you but will not be able to talk to you.