June 2021 Eclipse Festival of Frequency Measurement

Calling all stations: Join us for
The June 2021 Arctic Eclipse Festival

07 June 2021 0000 to 12 June 2021 2359 UTC


Alternate language options:
French: F
Norwegian: Bokmål


Changes in ionospheric electron density caused by space weather and diurnal solar changes are known to cause Doppler shifts on HF ray paths. For example, see Figure 7 in Boitman et al., 1999.  As part of the WWV centennial, 50 stations collected Doppler shift data for the original Festival of Frequency Measurement, demonstrating the value of volunteer participation in collecting this data. This June, we request that all amateur radio stations, shortwave listeners, and others capable of making high-quality HF frequency measurements help us collect frequency data for the June 10 annular eclipse. Researchers will use the crowdsourced data to investigate the superimposed effects of auroral particle precipitation and the eclipse on Doppler shift. 
All you need to collect data is an HF rig connected to a computer running open-source software. A precision frequency standard, such as a GPS-disciplined oscillator, is desired but not required to participate. All ham operators and shortwave listeners around the globe are invited to join in, even if your station is far from the path of totality. Last year's eclipse festivals included over 100 participants from 45 countries. The experiment will run from 7-12 June. All participants will receive QSL certificates and updates as the data is processed. This is a pilot experiment for HamSCI's Personal Space Weather Station project, which seeks to develop a global network monitoring the geospace environment. 



Contact information:

Kristina Collins: kd8oxt@case.edu


Research Questions

  • This eclipse crosses the auroral oval. When observing Doppler shift, what combined effects do we observe from the aurora and eclipse?
  • What properties of the ionosphere are we able to measure by observing the variation in these HF propagation paths?
  • What effect will the annular eclipse have on these propagation paths?
  • How do various measurement techniques for understanding the path variation compare?
  • Is there volunteer interest in collecting data in the regions near totality for this eclipse?



  • Promote international goodwill by working with citizen scientists around the globe
  • Measure Doppler shifts caused by space weather's effects on the ionosphere
  • Refine experimental procedures for future eclipse experiments
  • Develop digital signal processing for RWM




  • Data recording starts: 07 June 2021, 0000 UTC
  • Data recording ends: 12 June 2021,  2359 UTC

Please begin measurements before the day's start time and end them after the finish time, if possible.





The primary beacon for this experiment will be the Russian time standard station RWM on 9.996 MHz. If you are unable to receive it at your station, please try 10 MHz WWV or another station from this list. Experiment with your radio to see which stations are easiest for you to receive. 



How to Participate

1) Sign up on the Eclipse Festival mailing list: https://groups.google.com/g/eclipse-festival

2) Collect data according to the instructions on this page: hamsci.org/doppler-instructions
Use the instructions on collecting audio data in Audacity, not fldigi. 
If you collected data for the December 2020 Eclipse Festival, the procedure is very similar, except that the local oscillator frequency must be included in the filename. 

3) Submit data here: https://cwru.app.box.com/f/4c75fe21d8f744d980b61916704abd1f


Test Run

There will be an optional practice session on May 30th to select one or more beacon stations for the experiment. To participate, please listen for RWM (4.996 MHz, 9.996 MHz) and WWV (5 MHz, 10 MHz) on your radio and fill out the survey below. It's best to record around the same time of day as the eclipse (8 am UTC). If possible, please make a short recording with Audacity and upload it here