Swarm-E (formerly known as e-POP)

In the spirit of making data from the Radio Receiver Instrument (RRI) onboard Swarm-E (formally known as e-POP) more accessible to the ham radio community, we have converted RRI's data into a ".raw" format so that it can be ingested into open source software such as Gqrx or GNU Radio.  We have done this for all RRI data related to the 2015, 2017, and 2018 ARRL Field Days.

We encourage everyone to help us identify hams in RRI's signal.  You can use the Gqrx tool discussed here, or you can use your own technique.  If you decode a ham's call sign, if you would like to share your technique, or if you have any comments or suggestion contact us and let us know! 

To help organize your findings, you can download a spreadhseet containing that you can fill out and send to us.  Feel free to create your own spreadsheet or modify this one.  

Swarm-E (e-POP) RRI

Swarm-E RRI is a digital radio receiver with 4 3-m monopole antennas.  In most cases, the monopoles are electronically configured into a crossed-diople configuration.  In this configuration, RRI records I/Q samples for the two dipoles.  RRI has a sampling rate of 62500.33933 Hz, and a ~40 kHz bandpass, and can be tuned to anywhere between 10 Hz and 18 MHz.  More information on Swarm-E RRI can be found in the Swarm-E RRI instrument paper or Gareth Perry's recent Radio Science article.


  • Perry, G. W., Frissell, N. A., Miller, E. S., Moses, M., Shovkoplyas, A., Howarth, A. D., & Yau, A. W. (2018). Citizen radio science: An analysis of amateur radio transmissions with e-POP RRI. Radio Science, 53, 933– 947, https://doi.org/10.1029/2017RS006496.

Data Format

Each data file contains raw 32 bit complex I/Q samples for a given RRI dipole at a given frequency.  The samples are interleaved, e.g., IQIQIQIQ... The data files do not contain any metadata.  Any information regarding the time, frequency, and corresponding RRI dipole is in the file name.  

Filename Format

The filename format gives information about the time and data of the recording, the tuned frequency, and which of RRI's dipoles the recording corresponds too.  For example, gqrx_20150628_011614_3525000_62500_RRI_Dipole1 contains data recorded on Dipole 1, starting at 01:16:14 UT on June 28, 2015, at 3525000 Hz (3.525 MHz), at a sampling rate of 62500 Hz (RRI's 62500.33933 Hz sampling rate).


We have opted to convert the data into the .raw format so that it can be ingested into Gqrx.  There are other ways of analyzing RRI's data; this is just one way which we felt was as easy first step.  We are open to posting about other techniques on the HamSCI site as well.  To help get started with Gqrx, we have developed a How to play an RRI raw IQ file on Gqrx page.

Data Files

The data files may be downloaded directly from the Zenodo repository here


Congratulations to Dr. Kristina Collins, Ph.D., KD8OXT, who successfully passed her thesis defense on Friday, November 18, 2022, to earn her Ph.D. in Electrical Engineering from Case Western Reserve University! Dr. Collins’ thesis is entitled Development Of A Low-Cost Meta-Instrument For Distributed Observations Of Ionospheric Variability and focuses on the development of the HamSCI Grape Personal Space Weather Station Network. For the past three years, Dr. Collins has been the funded Ph.D. student on the National Science Foundation Distributed Array of Small Instruments Personal Space Weather Station Project and been an important and influential leader in the HamSCI community. She currently serves on the HamSCI advisory board, leads the HamSCI Eclipse and Frequency Measurement Festivals project and WWV/H Scientific Modulation team, and served as chair of the local organizing committee for the 2019 HamSCI Workshop held at Case Western Reserve University. Dr. Collins has been interviewed on the ARRL's Eclectic Tech Podcast, has peer-reviewed papers published in the American Geophysical Union's EOS magazine and IEEE Geoscience and Remote Sensing Letters, and has papers under review at Atmospheric Measurement Techniques and EGUSphere. Dr. Collins is excited to be joining the Space Science Institute in Spring 2023 as a postdoctoral research fellow through the NSF Office of Polar Programs. In her upcoming project at SSI, she will be developing sonification and mixed reality tools to explore magnetometer data. In addition to her radio and space science, she enjoys sailing, scuba diving, and film projection. She is also a member of the Luxuriant Flowing Hair Club for Scientists.

The High-frequency Active Auroral Research Program (HAARP) will be conducting a research campaign from Oct. 19 to Oct. 28, with transmissions taking place between 1400-0600 UTC (see table below for details). Actual transmit days and times are highly variable based on real-time ionospheric conditions. All information is subject to change. This campaign will be the most scientifically diverse ever conducted at HAARP; some particularly notable experiments include a first-of-its-kind attempt to bounce a signal off of Jupiter, investigation into possible causes of the airglow phenomenon known as STEVE (Strong Thermal Emission Velocity Enhancement), and testing the feasibility of using radio transmissions to measure the interiors of near-Earth asteroids. Experiments benefiting from amateur radio support or having citizen science applications are described in the HAARP Letter to the Amateur Radio Community, along with known frequency information. An official HAARP press release is available from the University of Alaska Geophysical Institute.


Members of the HamSCI team are in Charlotte, North Carolina this Friday through Sunday to present at the ARRL-TAPR Digital Communications Conference (DCC). The ARRL-TAPR DCC is an annual conference that presents leading ideas related to amateur radio electrical engineering and related fields. This year, members of HamSCI will be presenting on topics related to the upcoming 2023 and 2024 solar eclipses, the development of the Personal Space Weather Station, including the Grape HF Doppler Receiver, VLF receiver, and TangerineSDR wideband receiver. Additional presentations include advances in analysis of Traveling Ionospheric Disturbances observed both with large-scale amateur radio reporting systems (RBN/WSPRNet/PSKReporter) and the Grape Personal Space Weather Station, as well as the initial public release of pyLap, the new open-source Python-based interface to the PHaRLAP HF ray tracing toolkit. The entire DCC is being live streamed via the TAPR Digital YouTube Channel. You can download the conference agenda here.