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.
Supporting images
associated with this daily HF radio wave propagation
forecast can be found
at my new web page of
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.
#105 Issued Sunday April 15, 2018 at 1500
UTC
Important Solar, Space & Geomagnetic Weather Indices-
The
daily solar flux index numbers (DSFI) were 69.8 69.5 69.4
There had been
2 day in a row with a 2000 UTC daily solar flux index number
(DSFI) below
70.
The official daily sunspot number (DSSN) was 11.
There had
been 3 days in a row with a daily sunspot number (DSSN) greater
than
0.
In 2018 there had been 63 days with a daily sunspot number (DSSN) of
0.
Sunspot group #12704 was located near N11E24 with a relatively simple
a
class magnetic field capable of releasing very small B class solar
flares.
(((((On Sunday April 15, 2018 the unofficial daily sunspot number
(DSSN) was
0, as sunspot group #12704 has decayed into a spotless
plage.)))))
The 24 hour period 3 hour interval planetary K index (Kp) had
been at a
quiet geomagnetic condition of 2 1 0 1 2 2 1 2.
The 24 hour
period maximum and minimum solar wind speed ranged between 466 &
342
km/s.
Global Daily HF Radio Wave Propagation Forecast-
HF radio
wave propagation condition trend April 15, 2018- improving
HF radio wave
propagation condition trend April 16, 2018- improving
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.
