Pete et all,
I know that MF propagation conditions will be good tonight because I've been
accurately forecasting MF radio propagation conditions for 31 years. I don't
have time to explain now because I'm out the door on an all night fishing trip
but check out my MF propagation prediction guidelines below.
Here are some general guidelines concerning correlation of propagation indices
to actual expected HF/MF propagation conditions.
1.) Dropping indices numbers are better.
2.) For medium frequencies a solar flux under 150, under 100 better, 70 is best
for E layer multi hop.
Keep in mind though that the 10.7 cm (2800 mhz) solar flux index is not a
"reliable" gauge of ionization in our atmosphere for F layer HF frequency
refractions, as the energy of photons at this frequency is to low on the order
of one million times. However most are used to solar flux and sunspot number
and it's a hard habit to break. A better indicator is the background x-ray
flux. See #7 below.
3.) Solar flux of at least 100 for E valley-F layer ducting mechanism.
4.) Previous 24 hour Ap index under 10, under 7 for several days consecutively
is best.
5.) Previous 3 hour Kp index under 3 for mid latitude paths, under 2 for high
latitude paths, 0-1 for several days consecutively is best.
6.) Energetic protons no greater then 10 MeV (10+0) for 160/120 meters and no
greater then (10-1) on MF broadcast band.
7.) Background x-ray flux levels less than C1 for several days consecutively
for 160/120 meters and less then B9 for MF broadcast band but A9 or less best.
8.) No current STRATWARM alert.
9.) IMF Bz with a (positive number) sign, indicates a lesser chance of high
latitude path auroral absorption/unpredictable refraction or scattering of MF
RF signals, when the Kp is above 3.
10.) A 0 (zero) or better (positive number) Dst index as related to the
Equatorial Ring Current.
Also my HF/MF propagation theory site at http://www.kn4lf.com/kn4lf8.htm .
73,
Thomas F. Giella, KN4LF
Retired Space & Atmospheric Weather Forecaster
Plant City, FL, USA
Grid Square EL87WX
Lat & Long 27 58 33.6397 N 82 09 52.4052 W
kn4lf@arrl.net
Propagation eGroup: http://lists.contesting.com/mailman/listinfo/propagation
KN4LF Daily Solar Space Weather & Geomagnetic Data Archive:
http://www.kn4lf.com/kn4lf5.htm
KN4LF Amateur & SWL Radio History: http://www.kn4lf.com
Plant City, FL CWOP Weather Station #CW2111 Live Data:
http://www.kn4lf.com/index.html
Plant City, FL Daily Climatological Weather Data Archive:
http://www.kn4lf.com/kn4lf22.htm
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