Optimal Working Frequencies (MHz) for: US MIDWEST :: NW7US :: HFRadio.org
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Gain the on-air edge: This article explains how the ANTENNA is the key! -> Read this introduction to Antenna Modeling


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Solar Cycle 24 Smoothed Sunspot Progress
Solar Cycle 24 10.7-cm Monthly Progress
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Solar Sunspot Cycle 24 Progress

Solar Cycle 24 Smoothed Sunspot Progress
Solar Cycle 24 10.7-cm Monthly Progress
[ Solar Cycle Details ]




This page was rendered on 21-Dec-24 1158 UTC.
This page was first created in 1998.

Current Sunspot Cycle 24 Activity and Space Weather

Sun Spots: 148 as of 12/20/2024 :: 10.7-cm Flux: 184 SFU
(SFU=Solar Flux Units)

X-ray Solar Flares:
6h hi [M2.5][1115Z 12/20] 24h hi [M2.5][1115Z 12/20]

Planetary A-index (Ap): 13 | Planetary K-index (Kp): 2.00
Solar Wind: 526 km/s at 3.0 protons/cm3, Bz is 5.0 nT
(Dec 21, 2024 at 1141 UT)
Optimal Working Frequencies (MHz) for: US MIDWEST

For December 2024 using
the predicted smoothed sunspot number (SSN)
and 10.7-cm Radio Flux (SFU).

Created by NW7US on July 04, 2011
These NW7US radio signal path propagation tables are set up to cover main regions of the world. Each chart displays the FOT (or Optimal Working Frequency) at each UTC hour, for the paths given.

These radio frequencies are a percentage below the MUF (Maxiumum Usable Frequencies), and should be acurate for about 80 percent of the month. However, if a geomagnetic storm, a solar flare, or other event occurs, there is no promise that a signal will actually make it through the path in question. Often, during ionospheric storms and solar events (like a solar flare), the FOT is lower, or the path might even be closed.

UTC Time:
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
TO/FROM US MIDWEST
CARIBBEAN
28
28
28
27
25
23
21
19
18
16
15
15
16
19
21
22
24
25
26
27
27
28
28
28
NORTHERN SOUTH AMERICA
30
30
29
27
24
22
21
19
18
17
16
15
15
18
21
23
24
26
27
28
29
29
30
30
CENTRAL SOUTH AMERICA
31
28
26
24
22
20
19
18
17
16
15
18
19
22
24
26
28
30
31
32
32
33
33
33
SOUTHERN SOUTH AMERICA
26
19
18
17
16
16
15
15
14
14
14
13
14
20
22
25
27
28
30
31
32
32
31
29
WESTERN EUROPE
17
15
14
13
12
12
15
15
14
14
17
18
20
21
22
22
23
23
23
23
22
21
21
19
EASTERN EUROPE
11
11
10
10
10
16
15
14
13
12
15
18
19
21
22
22
23
22
22
21
20
18
16
12
EASTERN NORTH AMERICA
21
21
20
20
19
18
16
15
14
13
12
12
13
15
16
17
18
19
20
20
21
21
21
21
CENTRAL NORTH AMERICA
10
10
9
9
9
9
8
7
7
6
6
5
6
7
7
8
8
9
9
9
9
10
10
10
WESTERN NORTH AMERICA
16
16
16
16
16
15
15
13
12
11
10
10
9
10
12
13
14
14
15
15
16
16
16
16
SOUTHERN NORTH AMERICA
18
18
18
18
18
16
15
14
13
12
11
10
10
11
13
14
15
16
17
17
18
18
18
18
HAWAII
25
26
26
26
26
26
25
23
21
19
18
16
15
15
14
14
16
18
19
21
22
23
24
25
NORTHERN AFRICA
23
22
20
18
17
16
17
16
15
15
17
19
20
21
22
22
23
23
23
24
24
24
24
23
CENTRAL AFRICA
20
19
17
16
15
15
17
16
16
16
17
19
20
21
22
22
23
23
23
23
23
23
23
22
SOUTH AFRICA
17
16
15
15
14
14
14
22
21
19
19
21
24
26
28
29
31
32
29
25
22
20
19
18
MIDDLE EAST
16
15
14
14
16
17
16
14
13
14
17
19
20
21
22
23
23
23
23
23
22
21
20
18
JAPAN
22
23
23
23
22
22
21
19
18
16
15
14
15
17
18
17
15
15
15
17
18
20
21
22
CENTRAL ASIA
23
23
23
23
22
21
20
19
17
15
14
13
15
17
19
20
21
19
18
17
16
17
19
21
INDIA
14
16
18
19
19
17
15
14
13
12
12
15
18
19
19
18
16
14
11
11
10
10
10
9
THAILAND
19
21
23
22
21
20
19
16
15
14
13
12
15
18
20
21
22
21
19
18
16
15
15
16
AUSTRALIA
33
34
34
34
34
33
32
30
27
25
23
21
19
19
17
17
16
15
15
14
19
25
29
32
CHINA
21
22
22
22
21
20
18
16
15
14
13
12
15
18
20
20
18
17
16
16
16
18
19
20
SOUTH PACIFIC
33
33
33
32
31
29
25
18
17
16
15
15
14
14
14
14
13
13
13
24
28
31
32
33


Available FOT Charts for:

[ US West ] [ US Central ] [ US East ] [ Hawaii ]
[ Northern South America] [ Central South America ] [ Southern South America ]
[ Western Europe ] [ Eastern Europe ] [ Japan ] [ Australia ] [ India ]

[ Main Propagation Center ]






Predicted SMOOTHED Sunspot Number And Radio Flux Values
With Expected Ranges
YR/MO
Smoothed Sunspot Number
Predicted/High/Low
Smoothed 10.7 cm Radio Flux
Predicted/High/Low


Purchase the STD Internet Space Weather & Radio Propagation Forecasting Course


Solar Terrestrial Dispatch (STD) is a world-leader in space weather forecasting services, as was demonstrated in late October and early November 2003 (Oler, C., "Prediction Performance of Space Weather Forecast Centers during the Extreme Space Weather Events of October and November 2003," published in the peer-reviewed scientific journal "Space Weather" by the American Geophysical Union in 2004). A copy of this paper is available here.

STD expertise is used to provide high-quality space weather forecast services to many electrical power companies across North America, guidance to spacecraft operators and consultation to many others.

STD has developed a special space weather course designed to teach individuals without any background how to predict space weather (see below). The STD Space Weather Course was the recipient of the Study-Web Academic Excellence award.

The course is available on-line as a small group of downloadable Adobe Acrobat Reader documents comprising over 630 pages of printed material (for sample pages, click here). You can therefore choose to study the material on your computer or print it out for study.

The course, if you choose the option, also includes the STD workhorse, Space Weather Information Monitor (SWIM) software, which is the most comprehensive space and weather information monitor in the world. The course (if you choose the option, below) also includes the STD's powerful and popular Proplab-Pro HF Radio Propagation Laboratory software! All software products are optional elaborate tools that will contribute to your application of the knowledge obtained through this course.

Purchasing the Course

Please choose one of the following course packages.
  • Purchase: The course alone (no software), delivered over the Internet (as a download).

      Now: $200.00 - normally $250 USD
    • Pay Online by clicking the PayPal button:
      Note: This is only the course - no software. You are paying for the knowledge and content.

  • Purchase: The course with all the software, delivered over the Internet (as a download).

    • SALE! BUY NOW AT $275.00 - compare to the normal price: $300 USD

    • Includes this software: SWIM, and PropLab-pro Version 3.0 (NEW!)
    • Pay Online by clicking the PayPal button:
      Note: You are paying for the knowledge and content of this course, PLUS GETTING THE SOFTWARE, TOO!

NOTE: After you finish ordering, through PayPal, please allow me time to process your order. I am not always in front of my computer, so it may take a while for me to finish the processing of your order. I shall e-mail you the moment I have processed the order, and will give you specific directions on how to download the Course file(s). PLEASE BE PATIENT WITH ME!

A list of the topics covered in this home-study course include:
  • The Sun
    • Basics of the Sun
    • Sunspots
      • Types of Sunspots
      • Sunspot Magnetic Fields
    • Solar Radiation and Radio Emissions
    • Solar Cycles
    • Techniques for Modelling Solar Cycles
    • Sources of Information and Imagery
  • Interplanetary Space
    • The Solar Wind
    • Magnetic Fields
    • Heliospheric Current Sheet
    • Solar Sector Structures
  • The Earth
    • Magnetosphere
      • The quiet magnetosphere
      • The disturbed magnetosphere
      • Understanding Magnetic Indices
      • Magnetic Storms
        • Sudden Storm Commencements (SSCs)
        • Gradual Storm Commencements
      • Geomagnetically Induced Currents (GICs)
        • Effects on Electrical Hydro Systems
        • Effects on Other Long Conductors
    • Ionosphere
      • Formation of Ionospheric Layers
      • Factors Affecting Ionospheric Layers
  • Solar Disturbances
    • Transient Solar Coronal Mass Ejections (CMEs)
      • Types and Structures of Coronal Mass Ejections
      • Understanding the Importance of CME Structures
      • Inferring CME Structures from Available Solar Data
      • Coronal Mass Ejection Detection Methods
      • Using IMPACT (software) to Aid in CME Disturbance Predictions
      • Solar Cycle Dependencies
    • Solar Flares
      • Basic Nature of Flares
      • Types of Flares
      • Flare Rating Systems
      • Significance of Proton Flares
      • Ground Level Events (GLEs)
      • Fast Transit Events
      • Interpreting Magnetograms
      • Determining Magnetic Shear and Flare Susceptability
      • Solar Flare (and Proton Flare) Prediction Techniques
      • Solar Flare Related Coronal Mass Ejection Prediction Techniques
      • Sources of Solar Flare Information
    • Solar Coronal Holes
      • Coronal Hole Basics
      • Recurrence
      • Solar Cycle Correlations
      • Associations with Near-Relativistic Electrons
      • Coronal Hole Related Disturbance Prediction Techniques
    • Filament Eruptions
      • Filaments and Prominences
      • Eruptive and Non-Eruptive Activity
      • Filament-Associated Coronal Mass Ejections
      • Filament-Related Disturbance Prediction Techniques
  • Auroral Activity
    • Basic Theory of the Northern/Southern Lights
    • Behavioral Characteristics of the Auroral Ovals
    • Sensitivity to Solar Disturbances
    • Affects on Satellite Health and Radio Communications
    • Mathematical Models of the Auroral Zones
    • Auroral Activity Prediction Techniques
    • Information Sources
  • Conditions Affecting Satellite Health
    • Atmospheric Drag
    • Surface Charging Anomalies
    • Deep Dialectric Charging Anomalies
    • Interplanetary Shocks
    • Magnetopause Crossings
  • Postulated Sun/Earth Climate Connections
    • Possible Long-Term Climatic Trends
      • Rainfall
      • Temperatures
      • Atmospheric Pressure
      • Storm Tracks
      • Ozone Correlations
    • Possible Short-Term Meteorological Trends
      • Pressure and Winds
      • Lightning
      • Storm Systems
      • Ozone Responses
  • Radio Propagation
    • Basic Theory (Non-Technical)
      • Characteristics and Components of Radio Signals
      • Understanding Plasmas
      • Importance of Electron Collisions
      • Appleton/Hartree Contributions
      • Signal Polarization and Coupling
      • Ionospheric Absorption
        • Deviative Absorption
        • Non-Deviative Absorption
      • Fading
      • Multipathing
      • Travelling Ionospheric Disturbances
      • Solar Related Disturbances
      • Structure of the Ionosphere
        • Ionospheric Layers
        • Importance of Sporadic-E
        • Effects of Spread-F
        • Solar-Cycle Dependencies
        • Models of the Ionosphere
          • Simple Mathematical Models
          • Numerical Maps
          • CCIR
          • URSI
          • The International Reference Ionosphere (IRI)
          • Others
        • Probing the Ionosphere
        • Probing Techniques
        • Probing Instruments
        • Sources of Ionosonde Information
    • Basic Ray-Tracing Concepts
      • Ordinary vs Extraordinary Signals
      • Becoming Familiar with Ray-Tracing Software
    • Ray-Tracing in Three-Dimensions
      • Ray-Tracing Software Considerations
      • Preparing for 3D Ray-Tracings
      • Performing 3D Ray-Tracings
      • Studying 3D Ray-Tracing Results
    • Vertical Radio Signal Propagation
      • Signal Reflection Behavior
      • Critical Frequencies
      • Ray-Tracing Vertically-Incident Signals
    • Oblique Radio Signal Propagation
      • Signal Refraction/Reflection Characteristics
      • Effects of Geomagnetic Activity
      • Effects of Solar Activity
      • Ray-Tracing Obliquely Incident Radio Signals
      • Determination of Maximum Usable Frequencies
        • Simple Empirical Methods
        • Ray-Tracing Techniques
      • Effects of Sporadic-E
      • Non-Great-Circle (NGC) Propagation
        • Responsible Conditions
        • Compensation Methods
        • Ray-Tracing Techniques to Analyze NGC Propagation
      • Chordal-Hop and Inter-Layer Ducting Propagation
        • Advantages and Disadvantages
        • Analysis using Ray-Tracing Techniques
      • Searching for and Exploiting Exotic Propagation Paths
        • Properties of Exotic Paths
        • Searching for Exotic Paths using 3D Ray-Tracing Techniques
        • Determining the Most Reliable Exotic Radio Paths
    • Ionospheric Disturbances
      • Solar Related Disturbances
        • Solar Flares and Related Coronal Mass Ejections
        • Coronal Holes and High Speed Solar Wind Streams
        • Filament Related Coronal Mass Ejections
        • Impact of Flare Related Radio Noise Bursts
      • Short Wave Fadeouts
      • Sudden Phase Anomalies
      • Sudden Frequency Deviations
      • Devastating Effects of Polar Cap Absorption
      • Disturbances and their Effects on Satellite Communications
  • Radio Propagation Prediction Methods
    • Short-Term Forecasting Techniques
    • Medium-Term Forecasting Techniques
    • Long-Term Forecasting Techniques
    • Sources of Forecasting Information
  • Applied Forecasting Techniques
    • Climatology
    • Pattern Recognition
    • Compiling Necessary Information
    • Exploiting Databases
    • Computer Related Aids
    • Studying Real-Life Examples
    • Developing Experience and "Intuition"
  • Field Experience
    • The STD SW Course presents you with some specific historic real-life scenarios. Using the information and techniques studied in this course, you are asked to develop your own space-weather and radio-propagation predictions. The actual real-life impacts are then studied and compared with your forecasts.
    • The Course presents you with several hypothetical (possible future) examples and ask you to develop your own forecasts.
  • Course Completed


Although this course is largely self-taught, STD will provide support if you run into difficulties. There are no prerequisites.



Data and images courtesy of IPS Australia, NOAA, NASA, SWPC, SIDC

Layout, analysis, commentary, and certain forecasts and content is
Copyright, 2024, Tomas David Hood (NW7US), all rights reserved.
No part, except for the space weather 'banners', may be copied without express permission.

Last Update: September 01, 2024