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


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.

HamSCI submitted two white papers to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. The first white paper, entitled Amateur Radio: An Integral Tool for Atmospheric, Ionospheric, and Space Physics Research and Operations, discusses the technical capabilities of the amateur radio community and the open scientific questions and space weather operational needs that can be addressed with these capabilities. The second paper, Fostering Collaborations with the Amateur Radio Community, talks about how the professional science space science community and the amateur radio community can work together for mutual benefit and provides recommendations for fostering this relationship. The National Academy of Sciences (NAS) is the body in the United States charged with setting the highest level science priorities for the United States. Every 10 years, the NAS conducts a decadal survey of the community to help set these priorities. This current Decadal Survey for Solar and Space Physics (Heliophysics) will be the guiding document for space science research and operations for NASA, the National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA), and congress from 2024-2033.

A new study by Sam Lo et al. from the Centre for Space at the University of Bath entitled "A Systematic Study of 7 MHz Greyline Propagation Using Amateur Radio Beacon Signals" was just published in the peer-reviewed journal Atmosphere. Abstract: This paper investigates 7 MHz ionospheric radio wave propagation between pairs of distant countries that simultaneously lie on the terminator. This is known as greyline propagation. Observations of amateur radio beacon transmitters recorded in the Weak Signal Propagation Reporter (WSPR) database are used to investigate the times of day that beacon signals were observed during the year 2017. The WSPR beacon network consists of thousands of automated beacon transmitters and observers distributed over the globe. The WSPR database is a very useful resource for radio science as it offers the date and time at which a propagation path was available between two radio stations, as well as their precise locations. This paper provides the first systematic study of grey-line propagation between New Zealand/Eastern Australia and UK/Europe. The study shows that communications were predominantly made from the United Kingdom (UK) to New Zealand at around both sunset and sunrise times, whereas from New Zealand to the UK, communication links occurred mainly during UK sunrise hours. The lack of observations at the UK sunset time was particularly evident during the UK summer. The same pattern was found in the observations of propagation from Eastern Australia to UK, and from New Zealand and Eastern Australia to Italy and the surrounding regions in Europe. The observed asymmetry in reception pattern could possibly be due to the increase in electromagnetic noise across Europe in the summer afternoon/evening from thunderstorms. URL: https://www.mdpi.com/2073-4433/13/8/1340

Congratulations to Sam Lo and the entire team!