Well I’m back after being MIA for 8 days. Here in Lakeland, FL I survived
Hurricane Irma but it was very unpleasant. The eye wall went right over the top
of my location and we had an explosion of hurricane force winds and flying roof
shingles, tree branches, street signs and mail boxes.
Hello to my fellow
hamateur radio and SWL radio enthusiasts around the world.
Welcome to my
“not for profit” W4HM daily HF radio wave propagation forecast.
If you
find this "not for profit" 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 .
Feel free without prior
permission to redistribute this "not for profit"
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 my "not for profit"
daily HF radio wave propagation forecast can be found in my Facebook account at
https://www.facebook.com/thomasfranklingiellaw4hm
and
at
http://lists.contesting.com/mailman/listinfo/spaceweather but without
supporting images.
It's a NO SPAM voluntary "opt" in email type group
hosted by contesting on line (COL), so you have to sign up by using an existing
email address and creating a password.
And last but not least I also post
some snippets of solar, space and geomagnetic weather goings on and images in my
Twitter account at https://twitter.com/GiellaW4hm
.
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#257
Issued Thursday September 14, 2017 at 1700 UTC
Global Daily HF Radio Wave
Propagation Forecast-
We are now entering 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.
HF radio wave propagation conditions change hourly,
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).
HF
radio wave propagation conditions trend- steady state, which means neither
improving nor deteriorating.
Northern Hemisphere Radio Wave Propagation
Forecast-
80-60 (75-60) meters- fair at night and poor at day,
40-30
(41-25) meters- fair at night and fair at day,
20-17 (22-16) meters- very
poor at night and fair at day,
15 (13) meters- very poor at night and poor
at day,
12-10 (11) meters- very poor at night and very poor at
day.
And before you know it the winter solstice will be here. During the
northern hemisphere winter season the higher HF bands of 10-20 meters (11-19
meters) close sooner due to less sun light illuminating the ionosphere than in
the northern hemisphere. But the maximum useable frequency (MUF) is higher than
in the northern hemisphere as the F layer of the ionosphere is lower in height
and is more dense.
Southern Hemisphere Radio Wave Propagation
Forecast-
80-60 (75-60) meters- fair at night and poor at day,
40-30
(41-25) meters- fair at night and fair at day,
20-17 (22-16) meters- very
poor at night and fair at day,
15 (13) meters- very poor at night and poor
at day,
12-10 (11) meters- very poor at night and very poor at
day.
And before you know it the summer solstice will be here. Keep in
mind that almost daily during the southern hemisphere summer season you will
find that the 10 (11) meter bands will open via short north-south and east-west
propagation paths via sporadic E (Es). Also when multiple sporadic E (Es) clouds
form and line up favorably much longer propagation paths open up on east-west
paths. And last but not least north-south propagation paths occur across the
equator via trans equatorial propagation (TEP).
Received RF signal
strength scale-
Very Good- +1 over S9 Or Greater
Good- S7-9
Fair-
S4-6
Poor- S1-3
Very Poor- S0
Meter Band Equivalents
Ham &
SWL
160-> 90
80-> 75
60-> 60
40-> 49,
41
30-> 31, 25
20-> 22, 19
17-> 16,
15
15-> 13
12,10->
11
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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.
---------------------------------------------------------------------------------------------------------------------
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 © 1988-2017 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.
11.) Rising positive T index number. The T Index tracks with the F2
layer
critical frequency (foF2) and sunspot number (SSN) and indicates the
capability of the F2 layer to refract RF signals.
12.) Galactic
cosmic rays decrease to -3 units below zero and trending
towards
zero.
13.) Energetic electron flux levels no greater than 2 MeV
(2+0).
14. A solar wind speed of less than 300 km/s for several days
consecutively.
------------------------------------------------------------------------------------
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 my comprehensive HF radio wave propagation
forecast. This data is gathered and made public by the U.S. Government using
taxpayer $$$ (including mine).
However the solar, space and
geomagnetic discussions as well as the HF propagation forecast that I produce
from the RAW public domain
data is my personal intellectual property.
Therefore the solar, space and geomagnetic weather discussions and HF radio wave
propagation forecast contained herein is copyrighted © 1988-2017 by Thomas
F. Giella, W4HM.
Feel free without advanced permission to
redistribute this "not for profit"
solar, space and geomagnetic weather
discussion and HF radio wave propagation forecast, as long as you redistribute
it in its entirety and
give me credit for it.
Also solar, space and
geomagnetic weather 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.
