[SFDXA] W4HM Daily HF Radio Wave Propagation Forecast #2018-221

[Bill M]

> #221 Issued Friday August 10, 2018 at 1445 UTC
> 
> Important Solar, Space & Geomagnetic Weather Indices-
> 
> Solar activity was very low.
> 
> The daily solar flux index numbers (DSFI) were 70.3 69.6 70.2
> 
> There had been 5 consecutive days with a 2000 UTC daily solar flux index number (DSFI) less than 70.
> 
> The official daily sunspot number (DSSN) was 0.
> 
> There had been 7 consecutive days with an official daily sunspot number (DSSN) of 0.
> 
> There had been 41 of the past 44 days with an official daily sunspot number (DSSN) of 0.
> 
> In 2018 there had been 128 days with an official daily sunspot number (DSSN) of 0.
> 
> The 24 hour period 3 hour interval planetary K index (Kp) had been at a quiet geomagnetic condition of 1 1 1 1 1 0 1 1.
> 
> The 24 hour period planetary A index (Ap) maximum and minimum values ranged between 5 & 2.
> 
> The 24 hour period maximum and minimum solar wind speed ranged between 380 & 279 km/s.
> 
> Global Daily HF Radio Wave Propagation Forecast-
> 
> HF radio wave propagation condition “trend” on Aug 10, 2018- steady.
> 
> HF radio wave propagation condition “trend” on Aug 11, 2018- steady.
> 
> HF radio wave propagation condition “trend” on Aug 12, 2018- steady then minor deterioration.
> 
> Northern Hemisphere Radio Wave Propagation Forecast b-
> 
> 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- S0 at night and S3-4 at day,
> 
> 21000-21850 kHz- S0 at night and S1-2 at day,
> 
> 24890-24990, 25600-26100 kHz- S0 at night and S1 at day,
> 
> 28000-29700 kHz- S0 at night and S0 at day.
> 
> We are now firmly in the summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.
> 
> During the northern hemisphere summer season the 14000- 30000 kHz frequency range closes later due to more sun light illuminating the ionosphere than in the southern hemisphere. But the maximum usable frequency (MUF) is lower than in the southern hemisphere as heating in the F2 layer of the ionosphere is higher and the layer less concentrated.
> 
> Almost daily during the northern hemisphere summer season you will find that the 25600- 26100 kHz and 28000-30000 kHz frequency ranges 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).
> 
> Southern Hemisphere Radio Wave Propagation Forecast b-
> 
> 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- S0 at night and S3-4 at day,
> 
> 21000-21850 kHz- S0 at night and S1-2 at day,
> 
> 24890-24990, 25600-26100 kHz- S0 at night and S1 at day,
> 
> 28000-29700 kHz- S0 at night and S0 at day.
> 
> We are now firmly in summer/winter solstice type of HF radio wave propagation conditions. Globally HF radio wave propagation conditions are most unbalanced across the equator during this time period.
> 
> During the southern hemisphere winter season the 14000- 30000 kHz frequency range closes sooner due to less sun light illuminating the ionosphere than in the northern hemisphere. But the maximum usable frequency (MUF) is higher than in the northern hemisphere as the F2 layer of the ionosphere is lower in height and more concentrated.
> 
> 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.
>