I encountered this same phenomenom while driving through South Carolina
during the last week of June. I picked up signals from Kansas and Texas.

There are two types of "weird signals":
Troposheric ducting, which allows ground signals to extend for hundreds
of miles
Skip, in which the signals are bounced off an ionized layer in the
atmosphere. Signals over 1000 miles away are propagated this way.

"RandyP" wrote in message
...
Sounds like trophospheric ducting, where vhf and uhf signals propagate
beyond line of sight (do a search on google for tropospheric ducting for
more info that you care to know).

"Antonio" wrote in message
...
Today while driving, I was listening to WDOD 96.5 near Chattanooga,
somehow they were off the air..and instead there was a Mexican station
taking over the signal, very strong signal, fading and coming back,
then there was another Mexican station in the same channel.By the city
and frequency I found it to be XHRN-FM in Veracruz.It was the same on
other frequencies, like 94.5FM, there were 2 or 3 Spanish stations(One
of those was from Mexico City, Insituto Mexicano de la Radio
XHIMER,playing classical music). Then I moved to 101.7 and there were
another 2 spanish stations there.
Why does that happens and how often? I think it has to do with the
weather being hot and humid.
Any comments about that?