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Home > Propagazione > W4HM Daily HF Radio Wave Propagation Forecast #284

W4HM Daily HF Radio Wave Propagation Forecast #284

This is an abbreviated forecast.

Hello to my fellow hamateur radio and SWL radio enthusiasts around the world.

Welcome to my “not for profit” daily HF radio wave propagation forecast and solar, space and geomagnetic weather discussion.

If you find this “not for profit” daily HF radio wave propagation forecast and solar, space and geomagnetic weather discussion 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 and solar, space and geomagnetic weather discussion, 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 and solar, space and geomagnetic weather discussion  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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#248 Issued Tuesday September 5, 2017 at 1430 UTC

Global Daily HF Radio Wave Propagation Forecast-

HF radio wave propagation conditions trend- deteriorating

Northern Hemisphere Radio Wave Propagation Forecast-

80-60 (75-60) meters- poor at night and very poor at day,                                              
40-30 (41-25) meters- fair at night and poor at day,                                                  
20-17 (22-16) meters- fair at night and fair at day,                                                      
15 (13) meters- poor at night and fair at day,                                                            
12-10 (11) meters- very poor at night and very poor at day.
Keep in mind that almost daily during the northern 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).
                   
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.

During the southern 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.

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

We are now firmly in summer/winter solstice type of HF radio wave propagation conditions.

This means generally poor HF radio wave propagation conditions in the northern hemisphere especially at day and generally good HF radio wave propagation conditions in the southern hemisphere especially at day.

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 solstice.

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).

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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.

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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 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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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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