[HCDX] KN4LF Daily HF/MF Radio Propagation Outlook #2003-13
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[HCDX] KN4LF Daily HF/MF Radio Propagation Outlook #2003-13
KN4LF Daily HF/MF Radio Propagation Outlook #2003-13
http://www.kn4lf.com/kn4lf5.htm
Standard Disclaimer-
Note! I use "RAW" public domain data from the NOAA Space Environment Center, as well as other U.S. government organizations, to produce my "not for profit" propagation forecast outlooks. This data is gathered and made public by the U.S. Government using taxpayer $$$. However the forecast outlooks that I produce from the "RAW" public domain data, is my personal intellectual property. Therefore the propagation outlooks contained herein is copyrighted © 1988-2003 by Thomas F. Giella and the Florida Space And Atmospheric Weather Institute, all rights reserved. Reproduction of information herein is allowed as long as proper credit is given.
Also space weather forecasting is still an inexact science. The discussions, forecasts and outlooks are not official but for educational purposes only and are subject to human error and acts of God, therefore no guarantee or warranty implied
Date Format is YY/MM/DD
Published Saturday 03/09/06 At 1800 UTC
PAST 24 HOUR SOLAR, SPACE WEATHER AND GEOMAGNETIC INDICES-
Sunspot Groups- No sunspot groups currently contain twisted magnetic fields capable of producing very large or huge M and X class solar flares.
Solar Flux Readings- 109 108 108
Sunspot Number- 57
X-Ray Solar Flares- C-1 M-0 X-0
Averaged Background X-Ray Flux- B3.1
Energetic Protons >10 MeV (10+0)- None
Geo-effective (Earth Facing) Coronal Mass Ejections (CME)- None
Recurrent Coronal Hole #054 which became geo-effective on 03/08/28 and began impacting the geo-magnetic field with active Kp-4 conditions on 03/09/01 at 0622 UTC, ended it's negative influence on the geomagnetic field.
Recurrent Coronal Hole #55 will become geo-effective (Earth facing) on 03/09/06-07.
In the past 24 hour period the Ap index has been at active levels, with a peak of 23.
In the past 24 hour period the Kp index has been at active levels, with a peak of 4.
Here are some "general" guidelines concerning correlation of propagation indices to actual expected HF/MF propagation conditions.
1.) Dropping indices numbers are better, except for solar flux on HF.
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, as the energy of photons at this frequency is to low on the order of one million times.
2a.) For high frequencies a solar flux of 100 is okay, 150 better, above 200 best for F layer multi hop.
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.
8.) No current STRATWARM alert.
9.) IMF Bz with a (+) positive 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.
TODAY'S PROPAGATION LESSON #5-
E Valley-F Layer Propagation Ducting Mechanism/Chordal Hop Propagation-
Antenna polarization plays a large role in the success of a long haul DX contact. As a medium frequency RF signal traverses our planets magnetic lines of force in a perpendicular manner on high and mid latitude paths say between W3 land and SM, higher angle horizontally polarized signals are more readily absorbed then lower angle vertically polarized signals. On other propagation paths on the globe opposite results can be found, i.e. horizontally polarized signals suffer less absorption on a propagation path between VK6 and W4.
You would expect a true long path QSO on 160 to be theoretically possible but improbable on most paths during any season. However a G to VK long path might be possible if the E-valley/F-layer ducting propagation mechanism or the Chordal Hop propagation mechanism is involved. A 160 meter signal can traverse a daylight path via these propagation modes if the transmitted signal enters/exits at each end of the path at or near sunrise/sunset when the D layer ionization is weak (ionospheric tilting).
The majority of the time medium frequency RF signals in excess of approximately 3200 miles propagate via the E-valley/F-layer propagation mechanism or via the Chordal Hop (mostly on HF) propagation mechanism. High solar flux values can aid in long haul medium frequency propagation, as high solar flux values ensure a strong F-layer half of the E-Valley/F-layer duct mechanism. Typically the majority of transmit antenna's radiation must be focused under 40 degrees (25-35 deg. being optimum) to enter the E-Valley/F-layer duct and (((((lower angle vertical polarization is best suited for this))))).
If one is lucky on the receive end of a ducted medium frequency signal, a change in the vertical and/or horizontal electron gradient will allow the RF to drop out of the duct at your QTH.
A note, high solar activity in the form of increased ionization created by ultraviolet and X-ray radiation, can fill in the E-Valley/F-layer ducting region with medium frequency absorptive ionization and interfere with the E- Valley/F-layer ducting mechanism. In a sense the E/F layer duct is shut down and the medium frequency RF signal can only propagate between the E-layer and land/ocean surface, at a higher angle and with more signal loss. This closing of the duct can be reciprocal on each end of the propagation path or one way only. (((((When closing of the duct occurs the advantage of a low angle vertical radiator is lost, with a higher takeoff angle horizontal dipole making the contact still possible, albeit maybe weaker.)))))
Medium frequency radio waves possess elliptical polarization, with the signal splitting into ordinary and extra-ordinary rays. These rays can propagate in or out of phase, mainly out of phase. The out of phase extra-ordinary ray represents a 50% power loss on the receive end of a propagation path.
72 HOUR PROPAGATION OUTLOOK-
We will see continued periods of unsettled Kp-3 to active Kp-4 geomagnetic conditions today the 6th, with quiet Kp-<2 to unsettled Kp-3 conditions on the 7-8th. Unfortunately though we can expect a return to active Kp-4 to minor storm Kp-5 by the 9th, thanks to recurrent Coronal Hole #55.
GLOBAL HF 3000-30000 KC PROPAGATION CONDITIONS EXPECTED-
Low Latitude- Good
Mid Latitude- Good
High Latitude- Fair To Good
GLOBAL MF 300-3000 KC PROPAGATION CONDITIONS EXPECTED-
Expect fair then becoming good "Northern Hemisphere" domestic propagation conditions on east-west paths.
Expect poor then becoming fair domestic conditions on north "TO" south paths in the "Northern Hemisphere" out to approximately 1100 miles.
Expect good then becoming fair domestic conditions on south "TO" north paths in the "Northern Hemisphere" out to approximately 1100 miles.
Expect fair then becoming good "Southern Hemisphere" domestic propagation conditions on east-west paths.
Expect good then becoming fair domestic conditions on north "TO" south paths in the "Southern Hemisphere" out to approximately 1100 miles+
Expect poor then becoming fair conditions on south "TO" north paths in the "Southern Hemisphere" out to approximately 1100 miles.
"High latitude" Northern Hemisphere (TA) Trans Atlantic, (TI) Trans Indian, (TP) Trans Pacific and cross equatorial propagation conditions in excess of approximately 3200 miles should be fair then becoming good.
"High latitude" Southern Hemisphere (TA) Trans Atlantic, (TI) Trans Indian, (TP) Trans Pacific and cross equatorial propagation conditions in excess of approximately 3200 miles should be fair then becoming good.
"Mid latitude" Northern Hemisphere (TA) Trans Atlantic, (TI) Trans Indian, (TP) Trans Pacific and cross equatorial propagation conditions in excess of approximately 3200 miles should be good.
"Mid latitude" Southern Hemisphere (TA) Trans Atlantic, (TI) Trans Indian, (TP) Trans Pacific and cross equatorial propagation conditions in excess of approximately 3200 miles should be good.
"Low latitude" Northern Hemisphere (TA) Trans Atlantic, (TI) Trans Indian, (TP) Trans Pacific propagation conditions in excess of approximately 3200 miles should be good.
"Low latitude" Southern Hemisphere (TA) Trans Atlantic, (TI) Trans Indian, (TP) Trans Pacific propagation conditions in excess of approximately 3200 miles should be good.
Propagation Forecast Scales-
Excellent- +1 db Over S9 Or better
Good- S7-9
Fair- S4-6
Poor- S1-3
NOISE (QRN) OUTLOOK-
GLOBAL SATELLITE DERIVED LIGHTNING STRIKE DATA
(See Where Your QRN Is Coming From)
http://aviationweather.gov/gcd/graf/expconus.gif
http://aviationweather.gov/gcd/graf/exptropical.gif
During the 72 hour outlook period there will be "high" lightning induced QRN levels in low latitude areas of the Northern Hemisphere due to the proximity of the Inter-Tropical Convergence Zone (ITCZ) and tropical cyclones.
Northern hemisphere mid latitude regions can expect "moderate to high" lightning induced QRN tied to summer season thunderstorms, cold/warm/occluded fronts and associated extra-tropical cold core low pressure systems and tropical cyclones.
Northern hemisphere high latitude regions can expect "moderate" lightning induced QRN tied to summer season thunderstorms, cold/warm/occluded fronts and associated extra-tropical cold core low pressure systems.
During the outlook period there will be "high" lightning induced QRN levels in low latitude areas of the Southern Hemisphere due to the proximity of the Inter Tropical Convergence Zone (ITCZ) and tropical cyclones.
Southern hemisphere mid latitude regions can expect "moderate" lightning induced QRN, tied to winter season thunderstorms cold/warm/occluded fronts and associated extra-tropical cold core low pressure systems.
Southern hemisphere high latitude regions can expect "low" lightning induced QRN tied to winter season thunderstorms, cold/warm/occluded fronts and associated extra-tropical cold core low pressure systems.
Space Weather Scales-
Kp Indices-
G5 = Extreme Storm - Kp = 9
G4 = Severe Storm - Kp = 8
G3 = Strong Storm - Kp = 7
G2 = Moderate Storm - Kp = 6
G1 = Minor Storm - Kp = 5
Active - Kp = 4
Unsettled - Kp = 3
Ap Indices-
Ap 100-400 Severe Storm
Ap 50-99 Major Storm
Ap 30-49 Minor Storm
Ap 16-29 Active
Ap 8-15 Unsettled
Ap 0-7 Quiet
Correlation Of Kp To Ap Indices-
K- 0= A- 0
K- 1= A- 3
K- 2= A- 7
K- 3= A- 15
K- 4= A- 27
K- 5= A- 48
K- 6= A- 80
K- 7= A- 140
K- 8= A- 240
K- 9= A- 400
73 & GUD DX,
Thomas F. Giella, KN4LF
Plant City, FL, USA
KN4LF Daily Solar Space Weather & Geomagnetic Data Archive &
Daily HF/MF Radio Propagation Outlook http://www.kn4lf.com/kn4lf5.htm
KN4LF HF/MF Radio Propagation Theory Notes
http://www.kn4lf.com/kn4lf8.htm
KN4LF 160 Meter Amateur Radio Resources & More
http://www.kn4lf.com/kn4lf.htm
Florida Space & Atmospheric Weather Institute
http://www.kn4lf.com/fsawi.htm
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