Super DX by E layer

Recently, there have been reports of DX contacts on 6m between New Zealand and South America. For as many late spring/early summers as I can remember there have been 6m VHF QSOs between western Europe and Japan.  All these QSOs appear to be via E layer, but I think these are too far for multi-hop Es.

My own theory is this is some sort of chordal hop E layer propagation. It always seems to be in late spring/early summer and is linked to noctilucent clouds which form in the mesosphere around this time (late June, early July in the northern hemisphere).

I get the impression that these modes may well work at far higher frequencies, possibly even microwaves.

See https://sites.google.com/view/g3xbm4/home/vhfuhfmicrowaves/super-dx . 

See also John's blog at https://ei7gl.blogspot.com/ .