so ive been noticing the last couple weeks that 17m and 20m have been kind of all over the place. some days i can work europe no problem around 1400-1500 local and then the next day at the same time theres nothing, like the band just isnt there. checked pskreporter and there are signals showing up but im not hearing them at all on my end.

solar flux has been bouncing around a lot too, saw it up around 180 something last week then it dropped back down. i know higher SFI is generally better but ive had good 10m openings on days where the flux wasnt even that impressive so i dont fully understand how it all works together. is there a better resource than just checking the raw SFI number? feels like im missing something when im trying to predict whether its worth setting up for a DX session.

running 100w into a trapped vertical if that matters, been licensed about 2 years now

yeah the SFI number alone doesnt tell the whole story, thats the thing that tripped me up for a long time too. you also want to be watching the K-index and A-index for geomagnetic activity because even with a great flux reading, if K is up around 4 or 5 the bands can be completely dead or really weird. its like the flux tells you how much fuel the ionosphere has but the K-index tells you if somethings disturbing it.

DXmaps and the DX cluster are your friends for figuring out if a band is actually open before you sit there spinning the dial. if you see spots coming in from your part of the world on a particular band thats a good sign. also gray line is huge and a lot of people dont pay enough attention to it, that 20-30 minute window around sunrise and sunset can produce some wild openings even on days where the overall conditions look mediocre. voacap online is worth bookmarking too if you want to try to predict windows to specific regions.

I had the same frustrating thing happen during a DX expedition last month, VP9 was on and i kept seeing spots on the cluster but just could not pull them out of the noise on 17m. ended up catching them the next morning totally by accident when i was just checking the rig before work. sometimes the path just isnt there from your QTH even when other people are working them fine, takeoff angle from a vertical vs a beam makes a big difference too depending on the distance