On 5/23/2011 3:33 AM, Bill W4ZV wrote: > > g3ymc wrote: >> >> Sporadic E does not really affect 20m. >> > > N6BV makes a good case that Es on 10m-20m was a factor in the extremely high > number of EU QSOs (ITU Zone 28/29) experienced by the competitors near > Moscow at the WRTC in 2010. He does this by comparing VOACAP predictions > using F2 only versus F2 plus Es.
Perhaps the trap here is "sporadic," and maybe I fell into that trap by calling it "Es" to be short. There really is a non-sporadic E-layer, generally around 100 Km high, formed by longer wavelength X-rays and hard uV from the sun. At that height, the atmospheric density is high enough that recombination proceeds at roughly the same rate as ionization, so generally, and especially in the winter when solar radiation is more oblique, the E layer is weak at best and disappears completely at night. In the summer [either hemisphere], it is stronger and can begin to reflect [or refract] frequencies up to about 10 m. Es OTOH is very highly ionized [and small and very temporary] patches in the E-layer which accounts for many summertime 6m openings. Kevin is about 770 Km from me. On 20, he is at best just discernible in the winter, but is reliably S6-8 in the summer at ECN-20 time [1500 PDT which is really 1400 for the sun]. I've always assumed this was E-layer propagation. It certainly could be some other effect that is just positively correlated with summer, and of course, correlation does not imply cause. In Jun 2008, with my brand new K3 [#642], I decided to see if it really worked on 6m. The ATU matched my tribander, and I heard KH6FI calling CQ on SSB at about S6. I called him, he gave me 56, on a 3,900 Km path. I don't know what that propagation mode was, possibly multi-hop E-layer? Maybe F2, I don't remember the SFI. Incidentally, that is the only 6m QSO I've ever made in 57 years as a ham. In fact, it's the only time [to my knowledge] my call has been on 6m. At any rate, it is summer, and for whatever reason(s), six meters is opening a lot. 73, Fred K6DGW - Northern California Contest Club - CU in the 2011 Cal QSO Party 1-2 Oct 2011 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
