A few years ago I was spending the day at ARCC Kinloss and I had a conversation about comms with the duty controller. This was a former SAR Force SK pilot and SH Chinook pilot. "I'm not interested in talk-groups and all that stuff. I just want to press the button and talk and everyone understands what's going on."
What I take from that is that situational awareness is a valued commodity in SAR scenarios and that there are enough complicated things in helicopter cockpits already: especially when flying around near big bits of rock.
The radio discipline that Crab referred to is already instilled into most SAR pilots and at Kintail MRT it also features in the radio aide memoire that I encourage our folks to carry.
General MRT comms is in the process of moving from a widely-used radio band and during the next three or four years can be expected to partly or wholly move to digital VHF emissions. Airwave is history and the first major ESN migrations are programmed for summer/autumn 2018. ESN and other 4G/LTE rollouts will also provide improved opportunities for secure comms in some areas and satellite phones are in use by some teams and by SAR aircraft.
There is also the factor that these 1000m propagation barriers have a tendency to make it difficult for anyone at all to receive messages, so good luck with your Maplin-made-in-china scanner.
