Why hate anyone, that is why a communicator needs to be versed in all the
tools. That would be SSB, digital, CW, etc... You are forced, since
emergancies are not scheduled to take what ever mode works the best at the
specific time and get the information applied in a standard format
through.....
73 Chuck AA8VS
----- Original Message -----
From: "Jim Wiley" <[EMAIL PROTECTED]>
Cc: <elecraft@mailman.qth.net>
Sent: Monday, September 05, 2005 2:42 PM
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>
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