"umarc" wrote in message
...
(Antonio) writes:

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's called tropospheric ducting. When a layer of warm air forms above
a layer of cooler air, the boundary can reflect radio waves. This
can temporarily extend the range of FM signals. It is especially
common in summer months and over water. To broadcasters on the coast
it can be annoying, especialy when somebody's country station a
hundred miles away regularly wipes out one's classical station in
its home town.

Fine explanation of tropospheric ducting.

But that ISN"T the type of propagation involved in this report.

The propagation heard these past few weeks has been Ionospheric, by means of
the sporadic E layer, about 100 km (60 miles) above the Earth's surface. Go
back and read the information on the WA5IYX pages. Here are URLs again:

http://home.swbell.net/pjdyer/
http://www.qsl.net/wa5iyx/index.html