Maximum Usable Frequency (MUF)

Around the sunspot maximum we can see the MUF going much higher than we are used to. Take for example the 8m band, which is allocated to the Amateur Radio service in some countries and available to some on an experimental basis. Quite regularly, my 2.5W 8m FT8 is copied in the Caribbean, USA and Canada. This is on 40.680 MHz USB dial. This suggests the MUF is probably at 41 MHz quite often even on E-W paths. The MUF is usually higher on N-S paths.

For a long time, I have been advocating that 5 kHz at 8m be made available to the Amateur Radio service, narrow digital modes only, strictly non-interference, secondary, in the ISM band, low power, by application only.  I can see this only really appealing to true experimenters. It would appear the FCC and OFCOM (and the RSGB) are dead against, but I struggle to understand why when so much propagation research could be done. Even it permits were limited to around the solar maximum it would be useful.  Instead, in the UK we have to pay to do research - total madness and stupidity.