Hi Bill, NZ5N When AO40 was alive and well I experimented many QSO's with several stations in USA when the elevation of AO40 for me in JN70ES was already -2 or -3 degrees belove my free horizon using InstantTrack for tracking
The AO40 downlinh was obviously in 2401.300 MHz but my uplink was in 70 cm or 23 cm and my negative elevation was monitored by those stations in USA using all the same set of keplerian elements but with different tracking programs and all gives the same results that the elevation for me was negative. To explain this uncommon below the horizon propagation anomaly I believe that is my QTH location that play an important rule because my building is located only 100 meters from the beach and the antennas are 50 meters above the sea level and so it is possible that propably in presence of particular temperature and humidity and pressure conditions a duct similar to a wave guide is developed over the sea so that my signals and the satellite signals are traveling into the duct for many miles allowing the QSO to be made with AO40 belove my horizon. Another station i8KCL in my QTH wich home is many undred meters behind my back and more high them me over the sea level he was never able to receive AO40 with -2 or -3 degrees belove the horizon or made a two way QSO with the above negative elevation because probably owing of his home altitude he was not in condition to enter his signals into the suspected duct. I do not remember the call letter of the many stations in USA experimenting with me the above propagation anomaly but if some of them are reading this AMSAT-BB please drop a line in responce. Best 73" de i8CVS Domenico ----- Original Message ----- From: "Bill Dzurilla" <billdz....@yahoo.com> To: <amsat-bb@amsat.org> Sent: Sunday, March 13, 2011 1:25 AM Subject: [amsat-bb] Is it 100% impossible to work a satellite below thehorizon? > I was giving a presentation at our club meeting called Working DX on the Satellites and afterwards someone had a good question: is it at all possible that tropo, skip, or other form of enhanced propagation can enable a contact via a satellite below the horizon? > > It has never happened to me. Has it ever happened? > > 73, Bill NZ5N > > > > _______________________________________________ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
