Propagation

This page contains a dynamic collection of propagation information gathered from many different sources. This data is extremely useful for ham radio operators and shortwave listeners to help determine whether or not long distance radio communications are possible.


The current time is: 07:55 UTC on Thursday, March 23, 2023


Current Solar Indices from WWV
23-Mar-2023 at 0605 UTC
SFI = 159   A = 17   K = 1
Conditions during the last 24 hours
No space weather storms were observed for the past 24 hours.
Forecast for the next 24 hours
Space weather for the next 24 hours is predicted to be minor.
Geomagnetic storms reaching the G1 level are likely.

Solar Wind Data
Provides solar wind velocity and energetic particle intensity
Updated at: 0744Z on March 23, 2023

 Velocity (km/s):  474.1 
 Density (protons/cm3):  0.7 

(ACE satellite solar wind data has been intermittent)

Penticton Observatory SFI Measurement
WWV only updates its SFI reading once a day at 2100Z
The Penticton solar observatory takes measurements at 1700Z, 2000Z, and 2300Z
(WWV uses the 2000Z Penticton measurement)

 The Penticton Observatory SFI value on 22-Mar-2023 at 2300Z was:  156 

Three Day SFI and A-index Forecast
(updated daily after 2200Z)

This report issued on Mar 22, 2023 at 2200Z

  Date     SFI     A-index  
  23 Mar   155 20
  24 Mar   150 40
  25 Mar   145 30

Solar Activity Forecast
There is a slight chance for an isolated R1 (Minor) radio blackout over 22-24 Mar.
Geophysical Activity Forecast
There is a chance for an isolated G1 (Minor) storming period, are possible by late on 23 Mar if the CMEs from 20 and 21 Mar transit nearer to Earth than model output suggests. G2 (Moderate) geomagnetic storm levels are likely to be reached with the anticipated arrival of a CIR ahead of the onset of a positive polarity CH HSS on 24 Mar.

Recent Major Solar Flare Activity
(usually reported within 30 minutes of event peak)

  Date     Time     Magnitude  
  20-Mar-2023     0148Z     M1.2  

NOAA (American) Sunspot Number
This number is reported daily around 0225Z and reports
the number of sunspots observed in the previous 24 hour period

 The NOAA Sunspot number for 22-Mar-2023 was:  81 

 Most recent five days (oldest first): 58  35  73  75  70   

GOES-14 Background X-ray Flux
This value is reported daily around 0225Z and reports the
average background x-ray flux level as measured by the GOES-14 satellite

 The GOES-14 Background X-ray Flux level on 22-Mar-2023 was:  * 

 Most recent five days (oldest first): *  *  *  *  *   

Auroral Activity

Aurora (also known as "aurora borealis" or "northern lights") is caused by interaction between the Earth's magnetic field and the solar wind (a mix of charged particles blowing away from the sun).  During storms, enough of these charged particles make it through to the Earth's upper atmosphere that they interact with the earths natural magnetic field lines.  When enough of these particles collide, energy is released in the form of auroral light.  In addition to creating a pretty light show (mostly in upper latitudes), ham radio signals scatter off of these particles and can greatly enhance propagation on the VHF and UHF ham radio bands. High levels of aurora can also make HF ham radio propagation via polar routes difficult.

Real-Time
Northern Hemisphere
Auroral Activity

Northern Hemisphere Aurora

 

Real-Time
Southern Hemisphere
Auroral Activity

Southern Hemisphere Aurora

 

Click on thumbnails to view a larger image
Images courtesy of the NOAA Auroral Activity site


Solar X-ray Flux

This chart shows X-ray flux levels as measured by the GOES-13 and GOES-15 satellites.  The measurements (shown in red) are used to issue alerts when X-ray flux levels exceed certain levels.  Spikes on the chart correspond to solar flares.  Flares are considered "significant" when flux levels rise above the "M" level (as shown on the right side of the chart).  These large flares can often wipe out the ham radio and shortwave bands almost immediately and it can take minutes to hours for the bands to recover.  If the ham radio bands seem to go dead all of a sudden, it is always a good idea to check this chart to see if a large flare has occurred recently.

The Solar X-ray Flux graph is temporarily broken.
Click here to view it on the NOAA site

Dynamically updating plots:
1-minute and 5-minute X-ray    K-index
   Proton Flux   Electron Flux   GOES Magnetometer


Grey Line Map

The grey line is a band around the Earth that separates the daylight from darkness.  Radio propagation along the grey line is very efficient.  One major reason for this is that the D layer, which absorbs HF signals, disappears rapidly on the sunset side of the grey line, and it has not yet built upon the sunrise side.  Ham radio operators and shortwave listeners can optimize long distance communications to various areas of the world by monitoring this area as it moves around the globe.  This map shows the current position of the grey line terminator.

Grey Line Map

Click here to show a dynamically updating Grey Line map


Near-Real-Time MUF map

The following map shows Maximum Usable Frequencies (MUFs) for 3000 kilometer radio signal paths.  More importantly, the current sunspot number (SSN) and Planetary A-index are updated every 30 minutes on the bottom of this image.  Additionally, the grey line position, auroral ovals, and sun position are provided.  Click on the map for more details on how to use it.

Near-Real-Time MUF Map (with SSN & A-index)

This image courtesy of  Solar Terrestrial Dispatch


Current Sun Images

The images below are current views of the sun shown at different wavelengths of light as taken by SOHO and the Yohkoh soft-Xray telescope. Generally, more bright regions on the disk indicates more solar activity, which usually leads to higher flux levels (which also often leads to better ham radio and shortwave propagation).  Click on any thumbnail to view a larger image.

SOHO - 17.1nm

SOHO 17.1nm

SOHO - 19.5nm

SOHO 19.5nm

SOHO - 28.4nm

SOHO 28.4nm

SOHO - 30.4nm

SOHO 30.4nm

Sometimes you may see the text "CCD Bakeout" instead of the images.  This occurs when NASA does routine maintenance and calibration on the cameras.  For a more technical explanation, read NASA CCD Bakeout explanation.

Images courtesy of the SDAC at the NASA Goddard Space Flight Center


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Layout and dynamic reports created by amateur radio N6RT

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