so ive been noticing for the past couple weeks that 20m seems totally dead in the afternoons when it used to be my go-to for working europe from here in the midwest, and then randomly at like 7pm local time it just opens up like crazy for maybe 45 minutes and then closes again. happened three days in a row last week. checked the solar flux index and it was sitting around 145-150 which honestly i thought would mean decent conditions but maybe im reading too much into it

also 17m has been doing some weird stuff, had a solid opening to japan two mornings ago which i wasnt expecting at all, worked like 6 or 7 JA stations in a row and then nothing. my buddy down the road said he didnt hear anything on 17 that morning so either his antenna is the problem or i got lucky with some kind of short path thing. anyway just curious if others are seeing the same kind of inconsistent conditions or if somethings going on with the sun that i should be reading up on

yeah 20m has been pulling that late afternoon trick for a while now, its a greyline and seasonal thing combined i think. the path to europe from the midwest shortens up as the season changes and you get that weird window where the D layer absorption drops off right around sunset your time but europe still has some daylight left. flux in the 140s is actually pretty solid, better than we had for a long time, but high flux doesnt automatically mean stable conditions — you can get enhanced but also more volatile propagation when things are active

the JA opening on 17 doesnt surprise me at all. transpolar paths can do funny things and sometimes one station's takeoff angle just catches it while a guy a few miles away hears nothing. what antenna are you running? if youre on a dipole at low height you might actually be favoring higher angles which can work against you on some of those longer paths but sometimes helps on scatter type openings. worth checking dxmaps.com and pskreporter during those windows to see what the actual propagation footprint looks like in real time

im pretty new to hf still learning all this stuff but i had the same thing happen on 20m last thursday, heard a pile of europeans working some DX station i couldnt even make out the callsign of, tried to get in for maybe 20 minutes and then the whole thing just vanished. didnt know if it was me doing something wrong or just the band. good to know its not just my setup being weird i guess