Here are some useful notes on W6EL's program:
http://www.mdxa.org/w6elprop.html

It is contended that the W6EL program only uses the MUFs at the end points
of the path. For paths of something like 7 Mm or more this can introduce
large errors. Even the old, old graphical techniques used ionospheric
properties along the path.

Ionospheric propagation is such an interesting subject that I am not able to
understand why ND9B would not wish to "get deep in(to) propagation theory."
The ARRL's Antenna book has a useful and easy-to-read section on HF
propagation.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Roy Lewallen" wrote in message
...
A good, easy to use, easy to understand, and free propagation program is
available from http://www.qsl.net/w6elprop/. A google search on w6elprop
produces links to a couple of tutorials on using it.

Roy Lewallen, W7EL
(not to be confused with Shel Shallon, W6EL who has generously made his
W6ELProp program available at no cost)