Hello Glenn
Perhaps this was a misunderstanding and Thomas used incorrect words to explain a correct thinking. I just checked GeoClock and a Sunrise in Florida at this time of the year corresponds to almost a perfect Sunset in Bangkok, Thailand. Yes, Thailand is not geographically antipodal of USA but they match a Sunset/Sunrise Gray Line and this explains the good propagation noticed by Thomas. Marcelo -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Glenn Hau-ser Sent: Saturday, 6 September 2003 9:09 a.m. To: [EMAIL PROTECTED] Subject: [HCDX] Re: Antipodal Focusing Sorry to break this to you, but Thailand is nowhere near antipodal from the US. For starters both are in the Northern Hemisphere... Unfortunately there is little land on the opposite side of the globe from the USA --- in the Indian Ocean. 73, Glenn Hauser Yes Radio Thailand on 7260 kc at my local sunrise sure is stable here in Central Florida, even more so then R. Australia on 9580 kc. There is a propagation mode called anti-podal focusing. If you are at or very near the opposite side of the planet from the station you are receiving from and the aurora ovals are retracted, the RF signal can travel on all available geometric (GC) great circle paths, all coming together at the opposite side of the planet and adding up to a big signal. Antipodal focusing may explain Radio Thailand's big signal here in the U.S. Antipodal focusing is best at the fall/spring equinox of which we are fast approaching. A neat HF propagation project would be to keep track of Radio Thailand's 7260 kc signal every morning at local sunrise here in the U.S. for 365 days and plot it's signal strength versus the Ap index. 73, Thomas F. Giella, KN4LF Plant City, FL, USA EL87WX _________________________________________________________________ Need more e-mail storage? Get 10MB with Hotmail Extra Storage. http://join.msn.com/?PAGE=features/es ---[Start Commercial]--------------------- World Radio TV Handbook 2003 is out! Order it now! http://www.amazon.com/exec/obidos/ASIN/0823059677/hardcoredxcom ---[End Commercial]----------------------- ________________________________________ Hard-Core-DX mailing list [EMAIL PROTECTED] http://dallas.hard-core-dx.com/mailman/listinfo/hard-core-dx http://www.hard-core-dx.com/ _______________________________________________ THE INFORMATION IN THIS ARTICLE IS FREE. It may be copied, distributed and/or modified under the conditions set down in the Design Science License published by Michael Stutz at http://dsl.org/copyleft/dsl.txt ---[Start Commercial]--------------------- World Radio TV Handbook 2003 is out! Order it now! http://www.amazon.com/exec/obidos/ASIN/0823059677/hardcoredxcom ---[End Commercial]----------------------- ________________________________________ Hard-Core-DX mailing list [EMAIL PROTECTED] http://dallas.hard-core-dx.com/mailman/listinfo/hard-core-dx http://www.hard-core-dx.com/ _______________________________________________ THE INFORMATION IN THIS ARTICLE IS FREE. It may be copied, distributed and/or modified under the conditions set down in the Design Science License published by Michael Stutz at http://dsl.org/copyleft/dsl.txt
