Hi David, I did some experiments with VK2ZEN in Newcastle - 194km distance by GPS. We tried machine reception of CW, RTTY, PSK31 and MFSK16. There was a lot of QRN. MFSK16 provided 100% copy down to about 10 watts, with RTTY and PSK31 requiring about 30 watts for 100% copy. CW was woeful - about 30% machine copy (I think we were running it too slow to get good sync). This was on 80m at about 2300 local.
I would think from my experiments that running MFSK16 at reasonable power (say 50W for a 100W rig) would provide for quite reliable communications using NVIS. 73, Brett VK2TMG
