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


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.

A description of the hardware of the Grape Version 1 Personal Space Weather Station by John Gibbons N8OBJ, Kristina Collins KD8OXT, David Kazdan AD8Y, and Nathaniel Frissell W2NAF was published in the journal Hardware-X, entitled Grape Version 1: First prototype of the low-cost personal space weather station receiver. The full paper is available from https://doi.org/10.1016/j.ohx.2022.e00289.

A team of HamSCI researchers led by Nathaniel Frissell W2NAF just published a new article, First Observations of Large Scale Traveling Ionospheric Disturbances Using Automated Amateur Radio Receiving Networks, in the American Geophysical Union journal Geophysical Research Letters. The article looks at an event from November 3, 2017 to demonstrate how a large-scale disturbance moving through the ionosphere can affect the communications distances on the 14 MHz (20 m) amateur radio band. On this day, a 2.5 hour oscillation could be seen in the minimum distance of 14 MHz contacts recorded by the Reverse Beacon Network (RBN)Weak Signal Propagation Reporter Network (WSPRNet), and PSKReporter.