Very sad news. One of my HAM elmers, Petr OK1WPN, passed away on Thanksgiving Day 11/24/2011.
http://www.ok1kvk.cz/upload/ok1wpn/OK1WPN_parte.pdf
Petr was excellent designer. He published several "home brew" transceiver designs and many, many technical articles. It would be difficult to find a HAM with OK callsign who didn't know his work. Rest In Piece!