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 & 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 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 the realm of plasma 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.
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#103 Issued Friday April 13, 2018 at 1330
UTC
Important Solar, Space & Geomagnetic Weather Indices-
The
daily solar flux index numbers (DSFI) were 69.8 70.0 69.9
There had
been 23 days in a row with a 2000 UTC daily solar flux index
number (DSFI)
below 70.
But that streak just ended!
The official daily sunspot
number (DSSN) was 13.
There had been 11 days in a row with a daily
sunspot number (DSSN) of 0.
But that streak just ended!
In 2018
there had been 63 days with a daily sunspot number (DSSN) of 0.
A newly
emerged and numbered sunspot group #12704 was located near N11E51
with a
relatively simple b class magnetic field capable of releasing very
small B
class solar flares and an isolated small in size C class solar
flare.
The 24 hour period 3 hour interval planetary K index (Kp) had
been at a
quiet to unsettled geomagnetic condition of 2 2 2 1 2 1 2
3.
The 24 hour period maximum and minimum solar wind speed ranged between
548 &
461 km/s.
Global Daily HF Radio Wave Propagation
Forecast-
HF radio wave propagation condition trend April 13, 2018-
steady state
HF radio wave propagation condition trend April 14, 2018-
steady state
Steady state means that HF radio wave propagation conditions
are not
improving or deteriorating.
Northern Hemisphere Radio Wave
Propagation Forecast b-
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- 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
Southern Hemisphere
Radio Wave Propagation Forecast b-
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- 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
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.
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.
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. 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.
