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


The ARRL Frequency Measurement Test (FMT) is a bi-annual event that has its roots back to 1931! Back then, it was needed to ensure that Official Observers (OOs) could correctly callibrate their radios for monitoring and policing purposes. The FMT is still quite relevant today, but for different reasons. Today, the most significant source of error on a stable recieved signal will be due to ionospheric variability. Therefore, making frequency measurements is of great interest to the HamSCI community. These types of measurements are some of the inspiration for the HamSCI Festival of Frequency campaigns and the Low-Cost Personal Space Weather Station.  The FMT is a great way to get started in learning how to take precision ionsopheric measurements. A new Frequency Measurement Test mode added to the free FLDigi program makes it even easier to participate. You can now download an article entitled "Using Fldigi for the ARRL Frequency Measuring Test (FMT)" by Bob Howard, VE3YX, to help get you started. The next FMT will be November 13, 2020 from 0200Z-0524Z. More details are availble at https://fmt.arrl.org/ and in the November 2020 QST article by Ward Silver, N0AX. Thank you to FLDigi author Dave Freese W1HJK for his hard work in developing FLDigi and this new mode!

Ash Chaabane, 3V/KF5EYY, reports that a new Reverse Beacon Network (reversebeacon.net) node has been successfully installed in Tunisia.  There will soon be an Algerian and Libyan node when logistics permit.  The Tunisian node consists of a DX Engineering ARAV4-1P active vertical antenna (see the photo, contributed by Ash), a Red Pitaya 122-16 SDR, and CW Skimmer software by VE3NEA.  You can see the stations reported on several bands by the new node at https://dxcluster.ha8tks.hu/azimuthal_map/index.php?c=3V/KF5EYY&t=de. This node was part of a Yasme Foundation (yasme.org) project to install more RBN nodes in out-of-the-way places not currently home to a receiver.  The project aims to support both the amateur radio community and spaceweather/geophysics research community with propagation information from around the world and raise awareness of amateur radio's long-standing history of supporting science.  Additional nodes are planned for the Caribbean, South Pacific, and Russia, while other groups are installing nodes in Australia.

Video recordings of the third annual HamSCI Workshop are now available through the Ham Radio 2.0 YouTube Channel. The 2020 HamSCI Workshop for amateur radio operators and professional scientists was held Friday and Saturday, March 20-21, 2020, virtually on Zoom at The University of Scranton. The theme of the workshop was “The Auroral Connection,” and included addresses by guest speakers, poster presentations, and demonstrations of relevant instrumentation and software.