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
heliophysicist, terrestrial meteorologist/climatologist,
physical
oceanographer and one of the few on the planet with advanced
education and
forecast experience in both disciplines. In terrestrial
weather forecasting
I
have 45 years of experience and in solar, space and geomagnetic
weather
forecasting 34 years.
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 likeminded fellow radio enthusiasts.
Hams and SWLs that are
interested in solar, space & geomagnetic weather as
well as radio wave
propagation are a special group of people interested in
broadening their
knowledge in science.
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
in my Twitter account at
https://twitter.com/GiellaW4hm
Last
but not least here is my new HF radio wave propagation web page where
you
can sign up to receive this daily HF radio wave propagation forecast via
email. https://groups.io/g/w4hmradiowavepropagationforecast
but without
supporting images.
It's a NO SPAM voluntary "opt" in
email type group hosted by Groups.io, so
you have to sign up by using an
existing email address and creating a
password.
W4HM Solar Cycle 25
Forecast- Short and to the point.
Solar minimum may begin later this year
and may last longer than any
previous solar cycle in the 20th century. When
solar cycle 25 finally gets
underway it could be the weakest since the
middle of the 19th century.
Another Dalton type lesser grand solar minimum
may occur with a
corresponding cooling of earth’s climate. This would negate
anthropogenic
climate change if it were occurring which it isn’t.
On
February 1, 2008 I forecasted that solar cycle 24 would be the smallest
solar cycle in the past 100 years. That forecast verified. I also forecasted
that solar cycle 25 would be almost non nonexistent.
#144 Issued
Friday May 25, 2018 at 1445 UTC
Important Solar, Space & Geomagnetic
Weather Indices-
The daily solar flux index numbers (DSFI) were 73.6 73.7
73.8
There had been 3 days with a 2000 UTC daily solar flux index number
(DSFI)
of 70 or higher.
The official daily sunspot number (DSSN) was
39.
This is the highest daily sunspot number (DSSN) in a long
time.
Sunspot group #12712 was located near N13E75 with a relatively
simple beta
magnetic signature capable of releasing a very small in size B
class solar
flare and a small in size C class solar flare.
Sunspot
group #12711 was located near N06W41 with a simple alpha magnetic
signature
capable of releasing a very small in size B class solar flare.
Sunspot
group #12710 dissipated into a plage.
There had been 4 days in a row with
a daily sunspot number (DSSN) of higher
than 0.
In 2018 there had
been 80 days with an official 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 2 1 1 1 1 1 1.
The 24 hour period maximum and
minimum solar wind speed ranged between 491 &
370 km/s.
Global
Daily HF Radio Wave Propagation Forecast-
HF radio wave propagation
condition “trend” May 25, 2018- improving.
HF radio wave propagation
condition “trend” May 26, 2018- improving.
HF radio wave propagation
condition “trend” May 27, 2018- steady state.
Northern Hemisphere Radio
Wave Propagation Forecast g-
3150-3400, 3500-4100, 4750-5050, 5700-6300
kHz- S9 +1 to 9 at night and S1-3
at day,
6900-7800, 9200-9995,
10000-10150, 11500-12200 kHz- S9+ 1 to 9 at night and
S4-7 at
day,
13570-13850, 14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz-
S1-3 at
night and S8-9 at day,
21000-21850 kHz- S0 at night and S4-7
at day,
24890-24990, 25600-26100 kHz- S0 at night and S1-3 at
day,
28000-29700 kHz- S0 at night and S0-1 at day.
We are now in
the summer/winter solstice type of HF radio wave propagation
conditions.
Globally HF radio wave propagation conditions are most
unbalanced across the
equator during this time period.
During the northern hemisphere summer
season the 14000- 30000 kHz frequency
range closes later due to more sun
light illuminating the ionosphere than in
the southern hemisphere. But the
maximum usable frequency (MUF) is lower
than in the southern hemisphere as
heating in the F2 layer of the ionosphere
is higher and the layer less
concentrated.
Almost daily during the northern hemisphere summer season
you will find that
the 25600- 26100 kHz and 28000-30000 kHz frequency ranges
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).
Southern Hemisphere Radio Wave
Propagation Forecast g-
3150-3400, 3500-4100, 4750-5050, 5700-6300 kHz-
S9+10 at night and S4-7 at
day,
6900-7800, 9200-9995, 10000-10150,
11500-12200 kHz- S9+5 at night and S5-8
at day,
13570-13850,
14000-14350, 15005-15900, 17450-17950, 18068-18168 kHz- S1-3 at
night and
S9+1 at day,
21000-21850 kHz- S0 at night and S5-8 at
day,
24890-24990, 25600-26100 kHz- S0 at night and S1-3 at
day,
28000-29700 kHz- S0 at night and S1 at day.
We are now in
summer/winter solstice type of HF radio wave propagation
conditions.
Globally HF radio wave propagation conditions are most
unbalanced across the
equator during this time period.
During the southern hemisphere winter
season the 14000- 30000 kHz frequency
range closes sooner due to less sun
light illuminating the ionosphere than
in the northern hemisphere. But the
maximum usable frequency (MUF) is higher
than in the northern hemisphere as
the F2 layer of the ionosphere is lower
in height and more
concentrated.
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. It does outperform VOA CAP.
And
though this HF radio wave propagation forecast is produced based on
the
SIGINT_CAP software, 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 on every continent of the globe and tweak the forecast
manually if
and when necessary.
And last but not least I look at
ionsonde stations on every continent of the
globe.
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.
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). Also by
propagation path.
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.
Lower high frequency (80-30 meters) propagation conditions are
impacted in a
negative manner not so much by variations in the maximum usable
frequency
(MUF) along a particular propagation path and time but rather due
to
geomagnetic elevated geomagnetic conditions (Kp-3-4), storms (Kp-5
&
greater) that increase signal absorption via the E layer (the altitude
of
the radio aurora). Also increases in the lowest usable frequency (LUF) via
D
layer RF signal absorption due to hard x-rays, galactic cosmic
waves,
elevated background solar flux levels greater than B0 and energetic
proton
flux levels at energies greater than 10 MeV (10+0).
Higher
frequency (20-10 meters) propagation conditions are impacted in a
negative
manner by variations in the maximum usable frequency (MUF) along a
particular
propagation path and time due to the current sunspot number and
also due to
elevated geomagnetic conditions (Kp-3-4), storms of Kp-5 &
greater. Also
D layer RF signal absorption due to elevated (greater than B0)
background
solar flux levels. Also to a lesser extent elevated proton flux
at energies
greater than 10 MeV (10+0).
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.
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 and therefore also an art. 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.
