[OKDXA] Crozet Propagation

[Kim Elmore]

In the words of Lord Baden Powell: "Be prepared." In my own meager 
preparations, I decided to check propagation forecasts. It's natural in 
my line of work as a meteorologist for everyone to want and expect a 
weather forecast. We devote substantial resources, computational and 
human, to prepare, explain, and disseminate weather forecasts. As much 
as people complain about weather forecasts, I we're not nearly as good 
at forecasting HF propagation as we are weather: that's not meant as a 
dig. Rather, it means that we've not devoted the needed resources to it. 
Fundamentally, we don't yet know well enough quite how it all works to 
form a good mathematical model of the process. That said, we *do* have a 
good idea about what to expect *on average*, over a given period given a 
the time of year, time of day, path description, and SSN. Unlike weather 
models, which are dynamical (meaning they respond to outside forcing) HF 
propagation models are statistical.

To that end I decided to run some predictions of propagation from the 
Crozet Islands to central Oklahoma for Dec 2022, Jan, Feb, and Mar 2023. 
I chose a dipole at 10 m above the ground on the Crozet (transmit) end 
and a dipole at 15 m on our end. These are reasonable and manageable 
antennas. Stacked yagis on 120 ft towers make for stronger signals but 
don't create a path if there isn't one. We don't have the HAARP power 
levels needed to manipulate the ionosphere. I chose 100 W for the 
transmitter. So, what might we expect?

Since the reflector rejects any attachments, I sent images to Jeff so he 
could put them on our web site as an "online addendum." What I find 
interesting is that we get two openings a day: short path in the 
afternoon and long path in the morning. Neither traverses the polar 
regions or the (climatological) auroral circle, which means we shouldn't 
have too hard a time of it. In December, long-path gives us better than 
70% reliability on 15, 17, 20, and 30 m from roughly 14-17 UTC. our 
afternoon opening is best on 20 m between about 01-04 UTC.

Not much changes into March, which is roughly how good statistical 
models should behave.

The utility isn't so much "what will Feb 12, 2023 look like?", but more 
along the lines of "when should I be ready?"

MX, HNY, & CU in the Pileups,

Kim N5OP