so ive been trying to work some DX on 17 and 20m this week and the conditions have just been completely unpredictable. like monday afternoon 20m was wide open, i was hearing stations from japan and australia like they were next door, logged a bunch of JA's without even trying that hard. then tuesday morning i go to check the band and its completely dead. like nothing. not even noise really.

i've been watching the solar flux index on dxmaps and it was sitting around 145-150 which i thought was supposed to be pretty decent? but then the K index jumped up to 4 or 5 and i think that killed everything. i'm still learning how to read all this stuff so maybe im misunderstanding what the numbers actually mean in practice. does a high solar flux not matter as much when the K index spikes like that? feels like two steps forward one step back with this hobby sometimes

yeah the K index really does just nuke everything when it gets that high, even if the flux is good. basically what's happening is the solar flux tells you how much ionization the sun is putting into the ionosphere - more is generally better for HF. but the K index is measuring geomagnetic disturbance, and when that spikes it basically scrambles the ionosphere and absorption goes way up, especially at higher latitudes. so you can have great flux and terrible conditions at the same time if there's a geomagnetic storm going on. it's frustrating but that's just the nature of the beast.

when the K is high like that i usually drop down to 40m or even 80m at night, or just wait it out. conditions usually recover within a day or two after a storm passes. also worth checking the A index too, its kind of a 24 hour average of the K so it gives you a better sense of where things have been trending rather than just a snapshot.

same here man, tuesday was rough. i had a contact lined up with a guy in ZL land and we just could not make it work even with him running a kW. we tried for like 20 minutes and gave up. checked again wednesday evening and boom, 20m came alive again out of nowhere and i worked him no problem on my first call with 100 watts. propagation is honestly kind of magic sometimes haha. or black magic i guess depending on the day