Hi Jim, That was interesting. In 1958 I was on the National Geophysical Expedition to the North Pole on Drift station Alpha. KL7FLA and W9DVM/MM. We were floating. When we had severe aurora and you could turn all gains wide open and hear nothing, CW was always the first to be heard from Fairbanks and then SSB. That pattern never failed. Rig was a Collins KWS-1 and 75A-4. Just wanted to add another piece.
Phil K2/KAT100 Philip LaMarche LaMarche Enterprises, Inc. www.instantgourmetspices.com 727-944-3226 800-395-7795 pin 02 FAX 727-937-8834 NASFT #30210 W9DVM -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Wiley Sent: Monday, September 05, 2005 2:43 PM Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] Dropping the Code Test OK, guys, get ready to hate me. Here in Alaska, (that's a bit North of Michigan, to our flatlander friends) - Aurora is the norm. As in - every day, 365 days a year. Some days it's no big deal, some days it eats your lunch, it's just a fact of life. As often as not, SSB will get through when CW won't. FACT - not a typo! Apparently, with rapid changes in path length, which is what is responsible for the waterey sound of classic aurora reflection propagation, CW signals sometimes get lost in the process. I think this might be because CW signals are on just one frequency, and the destructive effects of multipath (selective fading) can wipe out individual dits or dahs, making copy of CW problematic. SSB, on the other hand, occupies a comparatively wide channel, and has energy on any number of frequencies within that channel. So, during times when aurora is very active, SSB apparently gets through because it has a sort of built in frequency diversity. If a hole gets punched in a SSB signal at one spot, there are still hundreds of adjacent frequencies that have an equal chance of being reinforced. The net result is that SSB suffers from rapid shifts in tonal balance as the "notched out" frequencies shift rapidly within the SSB pass band, but enough energy still remains that copy is possible. You will note that I am not saying CW is totally disabled - often times enough gets through that the incomparable DSP unit that sits on your shoulders can make enough sense of what it gets to still come up with copy. After all, VHF DX via auroral reflection is done all the time. But, and this is the important part, there are indeed times when SSB gets through when CW cannot. Man - what a disgusting idea. <grin> High latitude propagation is very different from what most "South 48" hams take for normal. It is nothing unusual for us to have total HF shutdowns lasting days on end. Even when bands are not being wiped out by solar storms, we get caught between between lukewarm MUFs and elevated LUFs - we frequently have access to only one band - 20 meters - because we are caught between the MUF / LUF squeeze, and even then we will hear only a few of the strongest signals. My station is not all that bad either - I run a TH7 antenna at 75 feet. When the band is open, I can use my K2, but when it's ratty even my Mark 5 driving an ACOM 2000A may not be enough. Oh well, there's always Pinochle - Jim, KL7CC EricJ wrote: It is my understanding from a communication with WB8RCR, a member of the Michigan Net, that CW is used because of a geographical anomaly . . . . . <snip> _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
