Specific relationships between Sun emissions and the ionosphere

[CAvoyager1960]

For long distance HF communication we talk about "skip" (skywave and the ionosphere) and how sometimes the signal can make multiple "hops". So lets assume... if I make a contact (10-11 meter) from california to somewhere in the east US (thousands of miles) can I assume that requires several hops or could that happen with a single skip? In other words, what would be an "average" skip distance (for each hop)? I know it is very unpredictable but just trying to get a general idea of the most likely scenerio. Is it even possible to do a single skip across this far away (over land... open sea is a different topic but feel free to discuss that too)
Side note: if a radio can only make contact (point to point) say 20 miles, how can it go much further shooting skip? The ionoshere is much higher than that (especially F layers) Is it simply that the air is thinner up high?

 

[EAFrizzle]

Although we speak of "skip" and "bouncing" radio wave, the ionosphere doesn't do that; it refracts the RF similar to the way lens refracts light. The degree of refraction is determined by the energy in the ionosphere for whatever frequency, and where the hops hit changes through the day.

Yesterday, I was getting hammered by west coast stations talking to east coasters on 11 meters. Couldn't hear any of the stations the Cali guys were talking with. This was in the late afternoon in Texas, so more energy is over California at the time, and less over the eastern seaboard. More refraction near California put the first hop right into me, then another one to the east coast. Less refraction over the east put their first ground hit in California, bypassing me completely.

 

[EAFrizzle]

Here's a video on HF skip that covers everything pretty well, especially about how the signals cross those distances

 

[CAvoyager1960]

Thank you... that was something I hadn't considered. It is actually very complex. I also know this has to do with the angle the signal hits the ionosphere (which relates to the specific antennas used) So you are telling me it's possible to go from west coast to east coast in a single skip? Crazy! I have talked to hawaii once and being it's ocean not land I wondered if that might have been a single skip.
Hey, one of those cali signal may have been me (I'm low power so maybe not... I'm 142) I hear many people from texas but also more south east (roof blocks me to the north)
BTW, I know about refraction (very into optics... cameras and telescopes) but what about the ground (or ocean) that doesn't "bend" the signal so must "reflect" it (I have mentioned this before... seemed to confuse people)

 

[CAvoyager1960]

I've seen that video (love "salty walt") but now after your explanation it makes more sense. I agree with walt... I love the challenge and wonder of HF propogation. If it was too easy, it wouldn't be as special.