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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.

The current time is: 14:34 UTC on Tuesday, June 06, 2006

 

Solar Wind Data
Provides solar wind velocity and energetic particle intensity
Updated at: 1427Z on June 6, 2006

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)

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

This report issued on Jun 05, 2006 at 2204Z

 

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

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

 

GOES-8 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-8 satellite

 

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 solar 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), radio signals scatter off of these particles and can greatly enhance propagation on 6 meters and above. High levels of aurora can also make HF propagation via polar routes difficult.

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-8 and GOES-10 satellites.  The GOES-8 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 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.

Dynamically updating plots:
5-minute X-ray    1-minute X-ray    Satellite Environment
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.  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 band as it moves around the globe.  This map shows the current position of the grey line terminator.

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.

This image courtesy of  Solar Terrestrial Dispatch

Current Solar 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 solar flux levels (which also often leads to better ham radio and shortwave propagation!).  Click on any thumbnail to view a larger image.

 

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

Layout and dynamic reports created by N6RT

Comments or Questions? Email webmaster@dx.qsl.net