so ive been on 10 meters almost every evening this week and i dont even know what to say. worked stations in Brazil, Japan, and then randomly a guy in South Africa all within like a 2 hour window last Thursday. my antenna is literally just a dipole in the attic, nothing fancy at all.

been watching the solar flux index and its been sitting up around 200-220 which i guess is pretty high? im still learning how all this solar stuff actually translates to band conditions. like i understand the basic idea that higher flux = better HF propagation but i dont fully get the mechanism. is this just cycle 25 doing its thing or has something specific happened recently that explains why 10 and 12 have been so good

also noticed some days it just completely dies even when the flux looks decent. had a morning where SFI was like 215 and i couldnt even hear Europe when the day before at the same flux number i was working them easily. whats up with that

yeah cycle 25 has really surprised a lot of people honestly, they were predicting it would be a moderate cycle but its been tracking above predictions for a while now. the flux being up in the 200s is genuinely exciting especially for those of us who had to suffer through the bottom of cycle 24 when 10m was basically a dead band for like 3 years.

the reason it dies even on high flux days comes down to a few things but the big one is geomagnetic activity. check the K-index and A-index alongside the SFI, if the K is above 3 or 4 you can have great solar conditions but the ionosphere gets disturbed and propagation goes to pieces especially on the higher bands. a solar flare can also cause a sudden ionospheric disturbance that basically blackouts HF for a few hours even in the middle of what should be a great day. DXMaps and the NOAA space weather site are worth bookmarking if you havent already, I check them before I even turn the radio on most mornings.

dude same, I worked like 40 countries on 10m last weekend and I was not expecting that at all. my setup is pretty modest too so its not like im running a kilowatt into a yagi or anything. just goes to show when the band is open it really doesnt matter that much.

one thing i noticed is that the openings seem to come in waves, like theres a really good window in the morning my time for Europe and then it kind of drops and then sometimes opens again toward afternoon for the Pacific. not totally consistent but thats been the rough pattern. somebody in our club mentioned something about greyline propagation playing into it too but i havent dug into that yet