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#94
Issued on Wednesday April 19, 2017 at 1430 UTC
Global Daily HF Radio Wave
Propagation Forecast-
HAMATEUR & SW BROADCAST HF BANDS:
Global
generalized HF radio wave propagation conditions
are
poor on 10-80
(11-75) 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
Tuesday April 18,
2017-
Solar activity was moderate.
Earth's geomagnetic field was
at storming level.
The three daily solar flux index (SFI) numbers were
77.5 85.6 85.8.
The official daily sunspot number (SSN) was 12.
In
2017 officially there were 30 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.
Recurrent sunspot group #12651 (#12644) was located near
N11E71 with a more
magnetically complex beta-gamma magnetic signature
capable of producing
medium size M class solar flares.
Unofficially
there was one earth facing but as of yet unnumbered sunspot
group. It was
located near
N12W26.
Two earth facing C class or larger solar
flares occurred. They
were
C5.5,
C3.3.
---------------------------------------------------------------------------------------------
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 nonexistent, 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
(geoeffective) directly earth facing coronal mass ejections (CME)
occurred.
But an earth facing coronal mass ejection (CME) was visible
on SOHO/LASCO
imagery but the plasma cloud was east directed.
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
2 1 0 1 1 1 2 3.
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
12
and 2,
which was at unsettled 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
C5.57.
The daily averaged vertical component (Bz) of earth's magnetic
field was at
+3.66 nT north.
The 24 hour period maximum and minimum
disturbance storm time index (Dst)
ranged between
+18 and -7
nT.
The 24 hour period maximum and minimum solar wind speed ranged
between
437 and 273 km/s.
There was a southern hemisphere
(geoeffective) directly earth facing (CH)
coronal hole #801. It produced
minor (Kp-5) geomagnetic storming during its
last trip across the earth
facing side of the sun.
There was a recurrent southern hemisphere
(geoeffective) directly earth
facing (CH) coronal hole #802 (#798). It
produced moderate (Kp-6)
geomagnetic storming during its last trip across
the earth facing side of
the
sun.
--------------------------------------------------------------------------------------
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.
