[W4HM Spaceweather] W4HM Daily HF Radio Wave Propagation Forecast #120
Thomas F. Giella
thomasfgiella at gmail.com
Sun Apr 30 10:58:11 EDT 2017
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#120 Issued on Sunday April 30, 2017 at 1400 UTC
Global Daily HF Radio Wave Propagation Forecast-
HAMATEUR & SW BROADCAST HF BANDS:
HF radio wave propagation conditions continue to slowly improve.
NORTHERN HEMISPHERE RADIO WAVE PROPAGATION-
80-60 (75-60) meters- good at night and poor at day,
40-30 (41-25) meters- good at night and fair at day,
20-17 (22-15) meters- very poor at night and good at day,
15 (13) meters- very poor at night and fair to good at day,
12 (11) meters- very poor at night and fair at day.
10 (11) meters- very poor at night and poor to fair at day.
SOUTHERN HEMISPHERE RADIO WAVE PROPAGATION-
80-60 (75-60) meters- good at night and poor at day,
40-30 (41-25) meters- good at night and fair at day,
20-17 (22-15) meters- very poor at night and good at day,
15 (13) meters- very poor at night and fair to good at day,
12 (11) meters- very poor at night and fair 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
This HF Radio wave propagation forecast is based on the NSACap HF radio wave
propagation prediction software and some daily analog tweaking.
The hamateur radio PSK31 RF signal levels received are based on 25 watts and
½ wave dipole up at 40 feet.
The hamateur radio CW RF signal levels received are based on 50 watts and ½
wave dipole up at 40 feet.
The hamateur radio SSB RF signal levels received are based on 100 watts and
½ wave dipole up at 40 feet.
The HF shortwave broadcast band AM RF signal levels are based on 100,000
watts (100 kw) and a typical VOA type curtain array antenna.
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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 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.
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Solar, Space & Geomagnetic Weather Conditions On
Saturday April 29, 2017-
Solar activity was very low.
Earth's geomagnetic field was at a quiet level.
The three daily solar flux index (SFI) numbers were 77.9 77.0 76.2.
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The official daily sunspot number (SSN) was 34.
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.
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 forecasted solar cycle 24 to be the weakest in the past 100 years
and that forecast verified. I also forecasted 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.
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Recurrent sunspot group #12651 (#12644) was located near N11W74 with a
magnetically simple alpha magnetic signature.
Sunspot group #12653 was located near S09W31 with a magnetically simple
alpha magnetic signature.
Sunspot group #12654 was located near N10 E41 with a magnetically simple
alpha magnetic signature.
Unofficially there were no earth facing but as of yet unnumbered sunspot
groups.
No earth facing C class or larger solar flares occurred.
There may have been an earth facing coronal mass ejection (CME).
Sunspot group #12653 produced a long-duration B3 flare at 30/0012 UTC and an
associated CME was observed in C2 coronagraph imagery beginning at 30/0236
UTC. Analysis of this event is underway in order to determine if the CME has
an Earth-directed component.
https://sohowww.nascom.nasa.gov/data/LATEST/current_c3.gif
No earth directed day side radio black outs occurred.
No earth directed collapsing magnetic filament eruptions occurred.
The twenty four hour period 3 hour interval planetary K index (Kp) was at
quiet geomagnetic conditions of
2 1 2 1 1 1 2 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
7 and 4,
which was at 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 24 hour period averaged energetic proton flux was at a background level
below 10 MeV.
The 24 hour period averaged background x-ray flux was at B3.09.
The 24 hour period averaged vertical component (Bz) of earth's magnetic
field was at
+1.10 nT north.
The 24 hour period maximum and minimum disturbance storm time index (Dst)
ranged between
-9 and -29 nT.
The 24 hour period maximum and minimum solar wind speed ranged between
405 and 344 km/s
and was directly connected by a high speed solar wind stream to recurrent
southern hemisphere earth facing (CH) coronal hole #802 (#798) which had now
set around the west limb of the sun.
There were no earth facing coronal holes.
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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.
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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.
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