[Elecraft] Recent band conditions

[Ron D'Eau Claire]

Hi Rod:

We're talking "weather" here... electrical "weather" but much the same as
the stuff that dumps rain on our heads or cooks us with sunshine. Only the
electrical weather that affects radio propagation is not so closely
monitored by so many stations and so well understood as the sunshine and
rain stuff. So, radio-wise, we are probably where the meteorologists were
back in the 1920s or 1930s. 

To answer your direct questions, the conditions we have seen are not at all
atypical for the "downside" of a solar cycle.

Beyond that, I don't know what level of information you are trying to find,
but there is a nice web page with a great little "flash" movie explaining
propagation at:
http://www.ae4rv.com/tn/propflash.htm

AE4RV did a very nice job showing how radio waves make it around the world
with one exception that I noted. He fell into the trap of explaining "skip"
as a repeated bouncing of signals from the ionosphere back to the earth and
back to the ionosphere again as they make their way around the earth. This
model doesn't hold up. The losses in the bounce off of the surface of the
earth are far too high to support the signal levels we see when working DX.
The more generally-accepted model is that under the right conditions our
signals are 'trapped' in the ionosphere, bouncing very efficiently between
layers for some distance before an anomaly causes the signal to be released
again to return to earth. Think of how light moves efficiently through a
fibre-optic tube.

That said, I forgive him. The "earth-sky-earth" picture been the STANDARD
model of propagation for my entire lifetime... since we didn't have an
"ionosphere" but instead our signals were reflected from the mysterious and
controversial "Heaviside" layer that a lot of scientists insisted could not
exist. And, besides, introducing a "new" concept in a basic discussion is
often more of a distraction than aid. 

AE4RV has a number of other interesting resources and information about
propagation.  


Ron AC7AC
K2# 1289


-----Original Message-----
Over the past few months I've read on QRP-L, the Elecraft list, and
elsewhere, comments about poor band conditions. What accounts for these
poor condition?

I know from monitoring the various space weather sites, that several
Coronal holes have appeared during the past few months. And there has
been a number of Geomagnetic storms. (A result of the particle streams
from the holes, and the odd CME).

Is it common to have such activity shortly after a Sunspot Cycle Peak?
How long will it last? How does this post Sunspot period compare to
previous post-peak periods?

I haven't found anything on the web that answers these questions, nor do
I know of any printed literature. Does anybody have a list of references
I can review?

73, Rod N0RC