Gladstone Signal Spotting Challenge FAQs

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The Gladstone Signal Spotting Challenge is named for Philip Gladstone, N1DQ, the creator and maintainer of the website, also known as the Digimode Automatic Propagation Reporter.  Philip has made a tremendous contribution to Amateur Radio operating, citizen-science and ionospheric research through the data ('spots') which are collected and stored on  This Wikipedia entry tells the story:

The first contest results for the GSSC have been tabulated and published:  GSSC 2023 Results

The following is an introduction to the GSSC.  Please visit the full GSSC Rules for detailed explanations of station requirements, and the post-event entry event and scoring process.  These FAQs are a brief, informal recap of the actual GSSC rules.  In case of conflicts or questions, the GSSC Rules should be considered the definitive resource.  The GSSC is but one event within the Festivals of Eclipse Ionospheric Science.

What is the Gladstone Signal Spotting Challenge?

The Gladstone Signal Spotting Challenge is planned to be a fun, friendly competition with a serious purpose.  Amateur radio operators (hams) and short wave listeners will be operating beacons and setting up receiving sites using WSPR, FST4W, PSK31 and Morse Code (CW).  (These activities are commonly referred to as 'spot generation', 'spot collection' and the resulting data, 'spots'.)  The spots generated and collected by GSSC participants will be used in scientific studies exploring the Earthly ionosphere’s reaction to the 2023 and 2024 solar eclipses passing over North America.  The studies should lead to a better understanding of the interactions between the Sun, the ionosphere, and radio wave propagation.  That research should benefit hams, professional broadcasters, satellite operators, and many other users of the radio spectrum.  

When will the GSSC occur? (Download and open the ICS file below to add the event to your electronic calendar)

  • April 8, 2024; 1400-2400 UTC; is the official 2024 GSSC event period.
  • The GSSC will start a few hours before the eclipse begins its transit across the US mainland, so baseline data can be gathered (it is important to know how well the ionosphere is refracting high frequency (HF) signals prior to the eclipse)
  • It will continue through the entire eclipse period, in order to study how high frequency (HF) propagation is affected by the eclipse (past experience suggests that ionospheric changes will be clearly visible in the data).
  • It will conclude a few hours after the eclipse transits beyond the US mainland, in order to observe and study the after effects of the eclipse, such as ionospheric recovery.

You do not have to operate the full GSSC period, though that would be most welcome.  If you only have an hour or two, try to schedule your operating when the eclipse path is nearest to your QTH.  That will raise the odds that your signals will be affected by the eclipse.   Eclipse paths can be seen at

GSSC 2024.ics

Geographically speaking, who should participate?

HF radio signals are rarely restricted to small geographic areas, so we welcome hams and radio enthusiasts from all over the world to set up WSPR and FST4W equipment (both transmitting and receiving) and also PSK31 and CW receivers (often called 'skimmers').   

What equipment is required?

Transmitting stations have many options (only a few are listed here, HamSCI is not recommending any specific method or vendor):

Receiving setups have many options (All require appropriate software, depending on the mode being received, e.g. WSJT-X, WSPRdaemon, fldigiCW Skimmer)

  • Standard HF transceivers with audio/computer interfaces
  • Most off the shelf software defined radios (SDRs)
  • Build-it yourself kits  (

Simple antennas, being minimally directive, are often best for these modes.  Verticals, dipoles, loops, installed indoors or out, will work well.  But - if all you have is a set of stacked beams hundreds of feet in the air - that's fine.  Please be sure to note your antenna system details in your post-event GSSC entry.

For receiving stations, a reliable Internet connection is highly desirable.  All spot collection software should be configured to forward the spot data, in real time, to one of the on-line aggregation sites, such as or  This relieves individual receiving stations from needing hardware and procedures to store and deliver the to spots to HamSCI researchers after the GSSC.

Where can I learn more about modes such as WSPR and FST4W?

The WSPR protocol is more than a decade old, yet is still widely used for propagation monitoring.  There are many web resources explaining WSPR and how to set up a WSPR station, perhaps the best place to start is at the WSJT-X software home page.  There are many YouTube sites to explore, one suggestion is linked here <>

WSJT-X contains a much newer protocol with exciting capabilities, FST4W.  The WSPR Daemon site has many details on that mode.

The HamSCI site has a list of publications on propagation research, including the use of WSPR data.

The GSSC looks like fun, but I also want to participate in the Solar Eclipse QSO Party.

Feel free to enter both events!  For example, you may wish to operate WSPR or FST4W transmitters on one or more one of the WARC bands while you operate in the SEQP.  FT4/8 operators:  The 2024 GSSC scoring will not include FT4 or FT8 receptions or transmissions.  Operators who enjoy those modes are encouraged to enter the Solar Eclipse QSO Party (SEQP).

Further suggestions?

Whether you are new or an expert in the areas of spot generation or spot collection, there's no need to wait for the GSSC to put your station to use.  Explore your options, assemble and operate your equipment as soon as you are ready.  You'll work the bugs out of your system well before the eclipse events.  Even better, you'll contribute valuable spot information to the on-line databases as Solar Cycle 25 ramps up.  You can follow our Sun's activity at and .

If you have questions regarding the Gladstone Signal Spotting Challenge, please send them to