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
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
and
at
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
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#33 Issued
Friday February 2, 2018 at 1530 UTC
Important
Solar, Space & Geomagnetic Weather Indices-
The daily
solar flux index numbers (DSFI) were 69.3 69.0 69.3.
There had been
8 days in a row with a daily solar flux number (DSFN) below 70, values that
occur at the bottom of a sunspot cycle (#24).
The official
daily sunspot number (DSSN) was 0.
In 2018 there
had been 17 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 geomagnetic
condition of
2 0 0 0 0 0 1
2.
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Global Daily
HF Radio Wave Propagation Forecast-
HF radio wave propagation condition trend February 2,
2018-
steady
HF radio wave propagation condition trend February 3,
2018-
steady
Northern
Hemisphere Radio Wave Propagation Forecast g-
3150-3400,
3500-4100, 4750-5050, 5700-6300 kHz- very good at night and poor to fair at
day,
6900-7800,
9200-9995, 10000-10150, 11500-12200 kHz- very good at night and fair at
day,
13570-13850,
14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- very poor at night and
good at day,
21000-21850
kHz- very poor at night and fair to good at day,
24890-24990,
25600-26100 kHz- very poor at night and fair at day,
28000-29700
kHz- very poor at night and 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
concentrated.
Southern
Hemisphere Radio Wave Propagation Forecast g-
3150-3400,
3500-4100, 4750-5050, 5700-6300- fair 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-
fair at night
and poor to fair at day,
21000-21850
kHz- poor at night and fair at day,
24890-24990,
25600-26100 kHz- poor at night and poor at day,
28000-29700
kHz- very poor at night and 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.
