Firstly an explanation about CB.
CB radio was originally devised to be a short range communication tool for the common man. Dont forget this was in the time when mobile phones
were a pipe dream and no-one had even considered the Internet. It was a fantastic tool for keeping in touch with friends and family in the community
and communicating from base to mobile. The range of a CB is typically around 3 miles in built up hilly areas to around 7-10 miles on flat land but,
depending on height, from a hilltop to hilltop could well be in excess of 100 miles.
So whats this "Skip" all about then ?

Well, in certain conditions it is quite possible to talk to people
hundreds of miles away, and sometimes even on the other side of
the world like they are just down the road. Sometimes you can
converse for quite a time, other times maybe just for a few

So how does it happen ?

Well its directly connected to sunspot activity and charged
particals caused by them. Different intensitys of solar flares
cause different reactions to the ionosphere.
Its a bit like a wormhole in space opening up only its a radio hole
on earth. Quite often its localised, ie. one area one end of the hole,
another area the other end. Sometimes its widespread and you
can get many countrys coming in all at once.
To be honest it would take far too much time to go into detail but for those of you who want to go into more detail there is a page full of info at
http://ecjones.org/propag.html which goes into great depths including when some of these "skip" occurances happened.

A point to note though is.. just because you can hear DX'ers from abroad doesnt mean they can hear you. Sometimes skip is one way. Also the
other station may hear dozens of people from the UK calling back to him even though you cant hear any of them. Some people use Linear
Amplifiers to give themselves an "edge" but other times you can contact them very easily.  Directional beams do tend to help but when the skips
in you really dont need them. Skip is different to normal signals, the size of your antenna is less important to normal transmitting where the bigger
the better is the normal rule of thumb. I have, myself, spoken abroad on standard power to Germany for well over half an hour..signal 9 to 30+ .. on
a DV27 !! ...........