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 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
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
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#96
Issued Friday April 6, 2018 at 1400 UTC
Important
Solar, Space & Geomagnetic Weather Indices-
The
daily solar flux index numbers (DSFI) were 66.7 66.4 66.8
The
2000 UTC daily solar flux number (DSFI) of 66.4 was the lowest so far in waning
solar cycle 24.
There
had been 17 days in a row with a 2000 UTC daily solar flux index number (DSFI)
below 70.
The
official daily sunspot number (DSSN) was 0.
There
had been 5 days in a row with a daily sunspot number (DSSN) of
0.
In
2018 there had been 57 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 to
unsettled geomagnetic condition of 3 2 1 0
1 2 3 2.
The
24 hour period maximum and minimum solar wind speed ranged between
445
& 343 km/s.
Global
Daily HF Radio Wave Propagation Forecast-
HF
radio wave propagation condition trend April 6, 2018-
steady state
HF
radio wave propagation condition trend April 7, 2018-
steady state
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, 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.