What Use Is An F-call?

What use is an F-call? Recently I spoke about digital voice communications. I made mention of the CODEC2 project being developed by Dave Rowe, VK5DGR. I also made reference of the kinds of things that digital voice improves, battery life, channel separation and bandwidth. One of the things I didn't mention, mainly because I still had to learn what it meant, is that CODEC2 has an estimated 13dB gain over Analogue FM. To explain what that actually means, you might recall that an S-point is 6dB, that means that if you use CODEC2, you gain more than two S-points, that's a little like turning up the transmitter power from 10 Watts to 200 Watts. If you look at it another way, if you have a Yagi and you install the same Yagi next to it, and connect it up properly, you've doubled the power and gained 3dB. If you do that again, you have 4 antennas and 6dB, if you do it again, you have 8 antennas and 9dB, again, 16 antennas or 12dB gain. So, the performance that we're talking about is something that you can either