My dusty old alinco working and responding well to the 27mhz single side band signals on the cb frequencies, that is still as popular today as yesteryear! imagine if an emp from the sun was to come are way or any other natural disaster that would render the internet useless? just a car battery and a length of wire would get you on the air and maintain communications with this old baby.
The propagation mode that these radio signals received on the alinco are bounced backed down to earth via the E layer which is the lowest part of the ionosphere which can be any where within a range of 90-160km above the ground, as you can see depending on the angle the signal leaves the antenna? and the length of the patches of ionization depends where you can communicate as well as the curvature of the earth.
There is a season for this particular event to happen and that is between the summer months of may to august, and is normally at its strongest between roughly the frequencies of 25-200mhz, it is also not dependent on sunspot activity as of other modes of propagation infact i have found it better during sunspot cycle minimums.
For a more in depth explanation click on the link below.