Greetings to my fellow hamateur radio and SWL radio enthusiasts around the
world.
Welcome to my “not for profit” daily W4HM Daily HF Radio Wave Propagation
Forecast.
It’s the only daily global HF radio wave propagation forecast produced on
the planet.
I'm a retired space and terrestrial meteorologist and one of the few on the
planet with advanced education & 44 years of forecasting experience in both
disciplines.
Created and disseminated by Thomas F. Giella, W4HM in Lakeland, FL, USA ©
1988-2018.
If you find this daily HF radio wave propagation forecast useful to your
hamateur and SWL radio activities, feel free to drop me a line and let me
know that at
thomasfgiella@gmail.com
I enjoy hearing from other radio enthusiasts.
Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.
Supporting images associated with this daily HF radio wave propagation
forecast can be found in my Facebook account at
https://www.facebook.com/thomasfranklingiellaw4hm
and at
http://lists.contesting.com/mailman/listinfo/spaceweather
but without supporting images.
It's a NO SPAM voluntary "opt" in email type group hosted by contesting on
line (COL), so you have to sign up by using an existing email address and
creating a password.
And last but not least I also post solar, space and geomagnetic weather
goings on and some images in my Twitter account at
https://twitter.com/GiellaW4hm .
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#56 Issued Sunday February 25, 2018 at 1600 UTC
Important Solar, Space & Geomagnetic Weather Indices-
The daily solar flux index numbers (DSFI) were 70.0 67.5 70.2
There had been 6 days in a row with a 2000 UTC daily solar flux index number
(DSFI) below 70.
The official daily sunspot number (DSSN) was 0.
There had been 8 days in a row with a daily sunspot number (DSSN) of 0.
In 2018 there had been 25 days with a daily sunspot number (DSSN) of 0.
The 24 hour period 3 hour interval planetary K index (Kp) had been at a
quiet to unsettled geomagnetic condition.
3 3 2 2 1 0 0 1.
The 24 hour period maximum and minimum solar wind speed ranged between
558 & 442 km/s.
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Global Daily HF Radio Wave Propagation Forecast-
HF radio wave propagation condition trend February 25, 2018- steady state
HF radio wave propagation condition trend February 26, 2018- deteriorating
Northern Hemisphere Radio Wave Propagation Forecast b-
3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz- fair to good at night and
poor at day,
6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- fair at night and fair
at day,
13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- poor at
night and fair at day,
21000-21850 kHz- very poor at night and fair at day,
24890-24990, 25600-26100 kHz- very poor at night and poor at day,
28000-29700 kHz- very poor at night and very poor at day.
Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0
During the northern hemisphere winter season the higher HF bands of 10-20
meters (11-19 meters) close sooner due to less sun light illuminating the
ionosphere than in the southern hemisphere. But the maximum usable frequency
(MUF) is higher than in the southern hemisphere as the F layer of the
ionosphere is lower in height and more dense.
Southern Hemisphere Radio Wave Propagation Forecast b-
3150-3400, 3500-4100, 4750-5050, 5700-6300- poor at night and poor at day,
6900-7800, 9200-9995, 10000-10150, 11500-12200 kHz- poor at night and fair
at day,
13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168, kHz-
fair at night and poor to fair at day,
21000-21850 kHz- poor at night and poor at day,
24890-24990, 25600-26100 kHz- very poor at night and poor at day,
28000-29700 kHz- very poor at night and very poor at day.
Excellent- S9+10 or >
Very Good- S9 +1-9
Good- S8-9
Fair- S4-7
Poor- S1-3
Very Poor- S0
Keep in mind that almost daily during the southern hemisphere summer season
you will find that the 10 (11) meter bands will open via short north-south
and east-west propagation paths via sporadic E (Es). Also when multiple
sporadic E (Es) clouds form and line up favorably much longer propagation
paths open up on east-west paths. And last but not least north-south
propagation paths occur across the equator via trans equatorial propagation
(TEP).
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This HF Radio wave propagation forecast is produced based on the SIGINT_CAP
HF radio wave propagation prediction software. I wrote it beginning in the
late 1980’s but I’m sorry to say that it can’t be distributed to the general
public.
And though this HF radio wave propagation forecast is produced based on the
SIGINT_CAP, I do check the actual band conditions at my location in the USA
and tweak the forecast manually where and when necessary. I also check
global HF radio wave propagation conditions via remoted radio receivers
around on every continent of the globe and tweak the forecast manually if
and when necessary.
The hamateur radio JT65A mode RF signal levels received are based on 5 watts
and ½ wave dipole up at 40 feet.
The hamateur radio PSK31 mode RF signal levels received are based on 25
watts and ½ wave dipole up at 40 feet.
The hamateur radio CW mode RF signal levels received are based on 50 watts
and ½ wave dipole up at 40 feet.
The hamateur radio SSB RF mode signal levels received are based on 100 watts
and ½ wave dipole up at 40 feet.
The HF shortwave broadcast band AM Mode RF signal levels are based on
100,000 watts (100 kw) and a typical high gain VOA type curtain array
antenna.
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Please keep in mind that this is a relatively simplified HF radio wave
propagation forecast, so as to keep it easily understandable and applicable
by the average radio enthusiast.
Globally HF radio wave propagation conditions are most evenly balanced
during the fall and spring equinoxes and most diametrically opposed during
the summer and winter solstices.
Conditions change daily, weekly, monthly, yearly and by decade, as the
sun rises and sets at different times and at different angles from the
ecliptic, as well as by radio wave frequency. This is due to changes in the
maximum usable frequency (MUF), lowest usable frequency (LUF) and F layer
critical frequency (FoF2).
The D and E layers also come into play through RF radio wave signal
absorption and refraction. And then there is sporadic E (Es) radio wave
propagation that can really throw a wrench into the gears so to speak.
Things like sporadic E (Es) radio wave propagation and lightning storm
static can impact HF radio wave propagation in an unpredictable manner and
mostly bad.
Ongoing solar, space and geomagnetic weather goings on also impact HF radio
wave propagation conditions in a negative manner.
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GENERAL GUIDELINES CONCERNING CORRELATION OF PROPAGATION INDICES TO ACTUAL
HF PROPAGATION CONDITIONS-
NOTE!!! The propagation indices "interpretations" are my personal
intellectual property. Therefore the radio wave propagation indices
interpretations contained herein is copyrighted © 1988-2018 by Thomas F.
Giella, W4HM, all rights reserved. Reproduction of information herein is
allowed without permission in advance as long as proper credit is given.
All 14 of the following indices have to occur as described below in order to
see the best global high frequency radio wave propagation possible,
something that happens rarely.
1.) Dropping geomagnetic field indices numbers are better, Kp of 0 best.
2.) A daily sunspot number of 150 or higher, 200 or higher best.
3.) A daily sunspot number of greater than 100 for routine stable formation
of the E Valley/F Layer ducting mechanism.
4.) Previous 24 hour Ap index under 10, fewer than 7 for several days
consecutively are best.
5.) Previous 3 hours Kp index fewer than 3 for mid latitude paths, fewer
than 2 for high latitude paths, 0 for several days consecutively is best.
6.) Energetic protons no greater than 10 MeV (10+0).
7.) Background x-ray flux levels greater than B1 for several days
consecutively, greater than C1 best.
8.) No current STRATWARM alert.
9.) Interplanetary magnetic field (IMF) Bz with a (positive number) sign,
indicates a lesser chance of high latitude path aurora
absorption/unpredictable refraction or scattering of medium frequency RF
signals, when the Kp is above 3.
10.) A -10 or better towards a positive number Dst index during the recovery
time after a geomagnetic storm, as related to the equatorial ring current. A
positive number is best.
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Standard Disclaimer-
Note! I use error prone RAW public domain data from the NOAA Space
Environment Center, other U.S. government entities and educational
institutions, to produce this daily HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).
However this daily HF propagation forecast that I produce from the RAW
public domain data is my personal intellectual property. Therefore this
daily HF radio wave propagation forecast contained herein is copyrighted ©
1988-2018 by Thomas F. Giella, W4HM.
Feel free without prior permission to redistribute this daily HF radio wave
propagation forecast, as long as you redistribute it in its entirety and
give me credit for it.
Also HF radio wave propagation forecasting is still an inexact
science. The forecasts are not official but for educational and hobby
related purposes only and are subject to human error and acts of God,
therefore no guarantee or warranty implied.
