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.

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


Save the dates! The next HamSCI workshop will be held virtually March 19-20, 2021. The HamSCI workshop is an annual meeting to share scientific and engineering ideas and results related to amateur radio, radio propagation, and radio science, as well as foster collaborations between the amateur radio and professional space science and space weather communities. The 2021 workshop will serve as both a team meeting for the Personal Space Weather Station project, as well as a forum for presentations on topics relevant to the HamSCI mission. The format will be similar to virtual March 2020 HamSCI workshop. Thanks to support from the National Science Foundation and The University of Scranton, the cost of this workshop is free. Abstract will be due February 15th. Information regarding abstract submission and other workshop details will be forthcoming. Please join the HamSCI Google Group to stay up-to-date on the latest information.

The IEEE Transactions on Antennas and Propagation have recently accepted new research by Chris Deacon G4IFX, Ben Witvliet PE5B, Simon Steendam, and Cathryn Mitchell M0IBG entitled Rapid and Accurate Measurement of Polarization and Fading of Weak VHF Signals Obliquely Reflected from Sporadic-E LayersThis research uses signals produced by a network of 6 meter amateur radio beacons across Europe.

HamSCI Member Joe Dzekevich K1YOW recently published his article "Winter Sporadic-E-Like Propagation on 6 Meters" in the November 2020 issue of CQ Magazine. Joe writes:

"The question was asked: why do we see sporadic-E like propagation in November and December, when many of the variables like UV radiation and solar exposure are at a minimum, unlike the very active sporadic-E summer months?  Much like it was shown that North Atlantic transatlantic 6m propagation during the summer was made more possible by strategically placed weather storm systems, it looks like a similar effect with very strong jet stream boundaries also affect sporadic-e like communications during the winter months.  This citizen science study is another example how amateur radio can contribute to science, and illustrates the great potentials for studies using ham radio data.  We have many amateur radio stations on the air, using modes like FT8 which make contacts on propagation paths that we thought were previously impossible."

A PDF of the Joe's article is made available here with permission from CQ Amateur Radio magazine.