Almost nothing has been written on the web about communications with Kiwi prior to his disappearance - as if there may have been little to none. The other pilots apparently did not know that something had happened to him at that moment. 100+ mile communications are easy in true line-of-sight such as between aircraft, be it using FRS, GMRS, CB, Ham, or aviation COM. The conditions apparently allowed plenty of altitude for this.
I am surprised maybe because sailplanes here in Southern Arizona regularly report their location, including altitude, observations of conditions, and what they plan next or that their flight is in jeopardy (low and not finding lift). This is true even when not team flying, which involves even more chatter.
I think the choice of Amplitude Modulation for aviation COM was/is profoundly unfortunate. I can't think of a worse option. People have died because of miscommunication due to the characteristics of AM. UAT and GPS may be the only radio technologies available to civilian aviators that are anywhere near the current state of the art and they operate near optimal theoretical capability. All of the other systems appear to have been chosen by other than experts in physics, communications, and information theory.

WTWisniewski (HZ)