December 2021 Eclipse Festival of Frequency Measurement


Calling all stations: Join us for
The December 2021 Antarctic Eclipse Festival

01 December 2021 0000 to 10 December 2021 2359 UTC





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. HamSCI's first attempt at a measurement of these Doppler shifts was during the August 2017 total solar eclipse.  We plan a careful measurement during the 2024 eclipse. 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 year,  all amateur radio stations, shortwave listeners, and others capable of making high-quality HF frequency measurements can help us collect frequency data for the December 4 solar eclipse across Antarctica.
However, this campaign will have an additional focus area: the development and testing of data collection and analysis software. Participants are encouraged to join or devise a project. Read on for details. 



Contact information:

Kristina Collins:



  • Promote international goodwill by working with citizen scientists around the globe
  • Develop and test new software for data recording and analysis
  • Measure Doppler shifts caused by space weather's effects on the ionosphere


Research Questions

  • What traveling ionospheric disturbances are produced by the eclipse, and can they be measured by citizen scientists?
  • What conjugate effects are produced by the eclipse, and can they be measured by citizen scientists?


Software Projects

If you would like to help test an existing project, look at the project list below and contact the lead for a project that looks interesting. Project leads are responsible for maintaining a list of software testers.

If you would like to develop a project, email with the subject line "Eclipse Festival Software Project." Include the following information:

  1. Project name
  2. Names, callsigns, and ORCIDs of development team
  3. Names, callsigns, and ORCIDs of testing team, if applicable
  4. Brief description and current status
  5. Project URL (i.e., a Github link)
  6. Contact information for the project lead developer, for participants interested in helping with testing. 


Project List

A list of software projects will go here. 

SNASH (SNASH Nimbly Archives Sound Headers)

Project Description: A Fall 2021 senior project at CWRU to replace Audacity for metadata recording. 
Development Team: Zachary Kadish orcid logo 16px, Martin Bui, Daniel Warner, Shivvanandh Mohan
Testing Team: TBD
Current Status: In development; will be seeking testers shortly. 
Project URL:

SDR Recording with GNU RadioGNU Radio - The Free & Open Source Radio Ecosystem · GNU Radio

Project Description: A GNU Radio flowgraph for measuring Doppler with your SDR.
Development Team: Marcus Leech
Current Status: Available for use. (If you record I/Q data, please post it to Zenodo or upload it below in a zipped file with a text document describing your setup.)
Project URL
Contact Information:


Live Audio Carrier Detection with GNU RadioGNU Radio - The Free & Open Source Radio Ecosystem · GNU Radio

Project Description: A GNU Radio flowgraph for measuring Doppler from audio using the PLL Detection function, as a flexible alternative to fldigi.
Developers and Testers: K0ZEL, KD8OXT, PE1MJA
Current Status: Testing existing code. Next steps: CSV logging, sideband detection. 
Project URL
Contact Information:


WWV/H Test Signal Analysis

Project Description: A special test signal is being transmitted on WWV/H to characterize the transmitters. The current version of the signal will run through January 30. 
Development Team: WWV/H Scientific Modulation Working Group
Current Status: Looking for ways to compare signal recordings ( to the ground truth (, and to develop citizen science experiments using the test recording.
Project URL 
Contact Information: or



Project Description: This repository contains a brief analysis result and the scripts (of shell, R, awk, etc.) used to obtain the frequency/amplitude data from the daily recorded output of Grape 1 (and any receiver applicable with 8kHz WAV file). I've been developing this set of scripts since the last year's December 2020 Festival. You need to specify the WAV filename, starting time (in UNIX/POSIX epoch), and pitch difference in ppm (which can be measured by how much *actual* time was spent for 86400*8000 samples of the WAV file (supposed to be one day if the recording timing has no error).
Development Team: Kenji Rikitake, JJ1BDX orcid logo 16px
Current Status: So far successfully made analysis of the data during 1 to 6 December 2021. The results are given in the own graphs and fldigi-compatible daily analysis data, as well as the text value files of frequency and amplitude information.
Project URL
Contact Information: Please use GitHub issues at


Software Tools

If you are interested in working on a software project, these tools will be of use to you:

GNU RadioGNU Radio - The Free & Open Source Radio Ecosystem · GNU Radio

GNU Radio is a free, open-source platform for digital signal processing. It will be used in several of the software projects. 

Installation Guides:
Chat Channels:


Zenodo is a FAIR Data repository which can be used to store referenceable files. Eclipse Festival participants are encouraged to submit datasets to Zenodo and include them in the HamSCI community page there, so that they may be easily listed and referenced later.


Regular Data Collection



  • Data recording starts: 01 December 2021, 0000 UTC
  • Data recording ends: 10 December 2021,  2359 UTC




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

How to Participate

1) Sign up on the Eclipse Festival mailing list:

2) Collect data according to the instructions on this page:

3) Upload your data to Zenodo or submit it via the link below.

4) Fill out the exit survey at the bottom of this page.


Frequently Asked Questions

Why this shift in focus?
While previous Eclipse Festivals have focused on crowdsourced data collection, the goal is to move to a truly co-designed citizen science model. Also, themes are fun.

Can I still collect data using audio or fldigi as I have in the past?
Yes! Follow the instructions from previous events, and upload your data here. Make sure to follow the filename convention! Your data cannot be analyzed if it isn't possible to tell who took it and when. If you have an unusual data format or a folder containing notes, send a zipped folder with a text file describing your station. Also, consider posting your data or work to and submitting a text document linking to the DOI number. 



Can software projects continue beyond the duration of the Eclipse Festival?
Yes, althoiugh this page will be closed and the list of software projects compiled on January 30th.