-------- Forwarded Message -------- Subject: Topband: 160m arrival angles Date: Sun, 17 Jul 2016 15:00:17 -0400 From: Carl Luetzelschwab <carlluetzelsch...@gmail.com> To: topb...@contesting.com BIll (AA7XT), There's some (but not much) measured data at HF of arriving elevation angles (for example, Wilkins et al, Epstein et al, Utlaut et al, Wilkins again et al, and Hallborg et al). But I've never seen any measurements at MF. The only paper that comes close (at least that I'm aware of) is by LaBelle. He measured arriving polarization from 50 KHz to 5 MHz. The only thing I can add are results of doing ray traces of the ordinary wave (the extraordinary wave is heavily attenuated on 1.8 MHz) with electron-neutral collisions and the magnetic field included. There appears to be three ranges of angles for propagation on 160-Meters at night. Low angles (roughly 0 to 15 degrees) give E hops. Medium angles (roughly 15 to 20 degrees) can give ducting. Higher angles (roughly above 20 degrees) give F hops. Whether ducting on 160-Meters occurs likely depends on the factors tied to the magnetic field. For a picture of these ray trace results, go to http://k9la.us. Click on the "160m" link on the left, and look at the "ray tracing on 160m" file at the top. As for E hops, it's tough for most of us to put lots of energy at very low elevation angles - but guys like VE1ZZ with take-offs over salt water may be able to take advantage of these very low angles. Carl K9LA _________________ Topband Reflector Archives - http://www.contesting.com/_topband ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Considering the previous thread, "Sloping Terrain vs Feedline Losses", I thought
this might be of interest.