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 and
one of the few on
the planet with advanced education and forecast
experience. In terrestrial
weather forecasting I have 45 years of experience
and in space weather 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 other 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.
Here is my new HF radio
wave propagation web page
https://groups.io/g/w4hmradiowavepropagationforecast
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.
#108 Issued Wednesday April 18, 2018 at 1430
UTC
Important Solar, Space & Geomagnetic Weather Indices-
The
daily solar flux index numbers (DSFI) were 69.3 69.3 68.8
There had been
2 days in a row with a 2000 UTC daily solar flux index number
(DSFI) less
than 70.
The official daily sunspot number (DSSN) was 0.
There had
been 3 days in a row with a daily sunspot number (DSSN) of 0.
In 2018
there had been 66 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
1 1 1 0 0 0 0 1.
The 24 hour period maximum
and minimum solar wind speed ranged between
363 & 270 km/s.
Global
Daily HF Radio Wave Propagation Forecast-
HF radio wave propagation
condition trend April 18, 2018- steady state
HF radio wave propagation
condition trend April 19, 2018- deteriorating
HF radio wave propagation
condition trend April 20, 2018- deteriorating
Steady state means that
HF radio wave propagation conditions are not
improving or
deteriorating.
Northern Hemisphere Radio Wave Propagation Forecast
g-
We are now in the fall/spring equinox type of HF radio wave
propagation
conditions. Globally HF radio wave propagation conditions are
most evenly
balanced across the equator during the fall and spring
equinox.
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
Southern Hemisphere
Radio Wave Propagation Forecast g-
We are now in the fall/spring equinox
type of HF radio wave propagation
conditions. Globally HF radio wave
propagation conditions are most evenly
balanced across the equator during the
fall and spring equinox.
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
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 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.
