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.
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#90
Issued on Saturday April 15, 2017 at 1500 UTC
Global Daily HF Radio Wave
Propagation Forecast-
HAMATEUR & SW BROADCAST HF BANDS:
Global
generalized HF radio wave propagation conditions
are
poor to fair
on 17-80 (15-75) meters
and
very poor to poor on 12-10 (11)
meters.
NORTHERN HEMISPHERE RADIO WAVE PROPAGATION-
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.
SOUTHERN HEMISPHERE RADIO WAVE PROPAGATION-
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.
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
Please keep in
mind that this is a relatively simplified HF radio wave
propagation forecast,
so as to keep it easily understandable 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 also 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.
---------------------------------------------------------------------------------------------
Solar,
Space & Geomagnetic Weather Conditions On
Friday April 14,
2017-
Solar activity was low.
Earth's geomagnetic field was
active.
The three daily solar flux index (SFI) numbers were 72.8 72.9
72.5.
The official daily sunspot number (SSN) was 11.
In 2017
officially there were 28 days with a daily sunspot number (SSN)
of
0.
Considering that solar minimum won't occur for approximately 2
more years,
+/- 1 year, observations daily SSN's of 0 occurring now is
unusually early.
Sunspot group #12650 was located near N08W01 with a
simple beta magnetic
signature.
There was one newly emerged but as of
yet unnumbered sunspot group located
near N13E09.
There was no earth
facing C class or larger solar
flares.
---------------------------------------------------------------------------------------------
In
2016 officially there were 32 days with a daily sunspot number (SSN) of
0.
Considering that solar minimum won't occur for approximately three
more
years, seeing daily SSN's of 0 occurring now is unusually
early.
As we move forward towards the next solar minimum between solar
cycle #24
and #25 the number of days with a 0 daily SSN will steadily
increase.
Eventually every day for many, many, many months will see a 0, the
big goose
egg.
In 2008 I fore casted solar cycle 24 to be the weakest
in the past 100 years
and that forecast verified. I also fore casted that
solar cycle 25 would be
virtually non existent, similar to the Dalton type
solar minimum that
occurred in the early 1800's. It will probably be very
difficult to
determine when solar cycle 24 ended and solar cycle 25
began.
---------------------------------------------------------------------------------------------
No
earth directed coronal mass ejections (CME) occurred.
No earth directed
collapsing magnetic filament eruptions occurred.
No earth directed day
side radio black outs occurred.
The twenty four hour period 3 hour
interval planetary K index (Kp) was at
unsettled to quiet geomagnetic
conditions of
3 3 2 2 3 2 3 2.
The Kp geomagnetic indices
are-
0-2- quiet
3- unsettled
4- active
5- minor geomagnetic
storming
6- moderate
7- strong
8- severe
9- extreme
10- our
atmosphere just got cooked off like on Mars and we are all dead.
The 24
hour period maximum and minimum planetary A index (Ap) ranged between
18
and 7,
which was at active to quiet geomagnetic conditions.
The Ap
geomagnetic indices are-
0-7- quiet
8-15 unsettled
16-29-
active
30-49- minor geomagnetic storm
50-99- major
100-400-
severe
>401- our atmosphere just got cooked off like on Mars and we are
all dead.
The daily averaged background x-ray flux was at
B1.22.
The daily averaged vertical component (Bz) of earth's magnetic
field was at
-2.77 nT south.
The 24 hour period maximum and minimum
Dst ranged between
-31 and -11 nT.
The 24 hour period maximum and
minimum solar wind speed ranged between
529 and 335 km/s.
There
was a southern hemisphere (geoeffective) directly earth facing (CH)
coronal
hole #801. In the next 1-2 days it could negatively impact earth’s
geomagnetic field in the form of minor (Kp-5) geomagnetic
storming.
--------------------------------------------------------------------------------------
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
propagation forecast that I produce from the RAW public domain
data is my
personal intellectual property. Therefore this radio wave
propagation
forecast contained herein is copyrighted © 1988-2017 by Thomas
F. Giella,
W4HM.
Feel free to redistribute this solar, space and geomagnetic
weather
discussion and HF radio wave propagation forecast, as long as
you
redistribute it in it's 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.
