>how to calculate the extent to which an electromagnetic signal is affected >by Faraday Rotation... I want to evaluate just how big an issue this is at >146 and 436MHz on the LEO-to-ground path. It increases linearly with total electron content of the signal path, and goes down with the square of the frequency. Nice little table in Davidoff's "The Satellite Experimenter's Handbook" gives some numbers for typical rotations at common ham frequencies, and gives some references to books you could look up at library. >if anyone >could recommend a well-written text on the subject, or even provide the >formulae required, I'd be most appreciative! Found the formula and a nice 4 page explanation in a book in my collection. This is an excellent book, but your chances of finding it locally are probably poor. I'd be happy to fax the 4 pages to you if you send me your fax #. NASA Reference Publication 1108(02) Propagation Effects on Satellite Systems at Frequencies Below 10 GHz Second Edition Warren L. Flock The little section on Faraday Rotation begins on page 2-13.