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 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.
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
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.
#116 Issued Friday April 27, 2018 at 1500 UTC
Important Solar, Space & Geomagnetic Weather Indices-
The daily solar flux index numbers (DSFI) were 71.8 69.4 69.1
There had been 1 day in a row with a 2000 UTC daily solar flux index number
(DSFI) less than 70.
There had been 8 days in a row with a 2000 UTC daily solar flux index number
(DSFI) greater than 70.
The official daily sunspot number (DSSN) was 17.
There had been 8 days in a row with a daily sunspot number (DSSN) greater
than 0.
In 2018 there had been 67 days with a daily sunspot number (DSSN) of 0.
Sunspot group #12706 was located near N02W27 with a simple alpha magnetic
signature capable of releasing a very small A class solar flares.
The 24 hour period 3 hour interval planetary K index (Kp) had been at a
quiet geomagnetic condition of 2 1 1 1 1 0 1 2.
The 24 hour period maximum and minimum solar wind speed ranged between 394 &
336 km/s.
Global Daily HF Radio Wave Propagation Forecast-
HF radio wave propagation condition trend April 27, 2018- deteriorating.
HF radio wave propagation condition trend April 28, 2018- steady.
HF radio wave propagation condition trend April 29, 2018- improving.
Northern Hemisphere Radio Wave Propagation Forecast g-
We are firmly 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- 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.
Southern Hemisphere Radio Wave Propagation Forecast g-
We are firmly 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- 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.
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.
