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


As Solar Cycle 25 begins, amateur radio operators look forward to the return of the exciting propagation conditions associated with solar maximum. The classic paradigm for solar cycle prediction is based on an 11-year sinusoidal pattern of sunspot numbers, with an official NASA-NOAA "consensus" prediction coming from a panel of experts evaluating an ensemble of different types of models. However, the underlying solar cycle mechanism is still not well understood and this consensus prediction can fall short. Scott McIntosh at the U.S. National Center of Atmospheric Research (NCAR) and his team have recently published a new method for predicting the time and amplitude of solar maximum, based on changes in the observed magnetic polarity in different regions of the sun. This new method predicts a stronger Solar Cycle 25 than the NASA-NOAA "consensus" prediction. HamSCI member Frank Howell K4FMH teams up with Dr. McIntosh to review this new methodology and its potential impacts on how we think about solar cycle predictions in a two-part article series currently featured on the cover of RSGB's RadCom magazine. More information can also be found at Frank's blog.

In November 2021, Dr. Martin Archer asked the HamSCI and Amateur Radio Community for help in determining the best way to sonify ultra low frequency (ULF) plasma waves measurements. Those results have just been published! From Dr. Archer:

"Our sense of sound can be a powerful tool in exploring and analysing data collected from satellites. But what is the best way to make this data audible? Space science researchers at Imperial College London asked for your input on which methods of making the sounds of near-Earth space audible produce the best results. We’re pleased to announce that the results of this survey have now been published in Frontiers in Astronomy and Space Sciences. The feedback was invaluable, providing clear recommendations on which methods were best. These are now being used by space scientists around the world to improve their science communication, public engagement, and citizen science. Thank you!"

HamSCI played a major role at the 2022 Dayton Hamvention, which was held in Xenia, Ohio May 20-22, 2022 at the Green County Fairgrounds The Dayton Hamvention is sponsored by the Dayton Amateur Radio Association and is the world's largest ham radio gathering, with over 32,000 attendees at the 2019 Hamvention. The Hamvention is an extremely important event for engaging with the amateur radio community, sharing ideas, developing collaborations, and sharing scientific results. This year, HamSCI hosted a booth, gave presentations in the Ham Radio 2.0 area, and hosted a forum. Support for the 2022 HamSCI Hamvention activities comes from The University of Scranton, the Yasme FoundationTAPR, the National Science FoundationNASA, and volunteers like you. This year, HamSCI will again host a booth in building 5 next TAPR, host booth talks in the Ham Radio 2.0 area, run demos, and the host HamSCI Forum.