Resources

HamSCI How-To Guides

Below you will find a variety of how-to guides that have been developed for various HamSCI projects.

Reverse Beacon Network (RBN)

The Reverse Beacon Network (RBN) is a network of Software Defined Radio (SDR) receivers which automatically decodes and reports spots of CW and digital signals. These guides describe how to setup multiband RBN skimmers and make recordings to a file.

Measurement, Calibration, and Calculation

Projects from Around the Internet

Propagation

Useful Links

The following links are useful to people who want to learn about ham radio, space science, and space weather.

Ham Radio Reporting Networks have been used by contesters and researchers alike to assess propagation conditions. Most of our current HamSCI projects rely heavily on one or more of these networks.

Setting up a Reverse Beacon

This is a how to page for Gqrx an "open source software defined radio receiver".  Gqrx has many bells and whistles, one of which is the ability to listen to "raw" IQ files, speficially, "raw" IQ files from RRI.  This page is desinged to help set-up and listen to "raw" RRI IQ files using Gqrx.

Currenlty, Gqrx is available for Linux, and some instance of Mac OS.  Information about that can be found here.  This instructions and screen captures shown here are from Ubutu 18.04 LTS.  These instructions will be very similar - if not identical - for a Mac Gqrx install.  Gqrx may be downloaded directrly from the site, or it may be installed through the normal Linux APT software.  Gqrx user support is provided via a Gqrx Google group.

As you will see, Gqrx has lots of options and settings.  Here we are only concerned with playing "raw" I/Q files assoicated with RRI's dataset.

 

Gqrx Startup

When starting up Gqrx (assuming that your install went smoothly) you should see something similar to the following screen-grab.

Gqrx_instructions_startup.png

 

Receiver settings

The raw I/Q files do not contain any metadata. RRI's settings related to the data file must be manually entered into Gqrx.  To do this, click on Configure I/O devices icon on the left side of the toolbar at the top of the window, as shown (the incon looks like a piece of computer hardware).  Then enter the important information contained in the file name of the RRI raw file into the Configure I/O devices window.  For example, here we have entered information for an RRI data file that was recorded at 7.025 MHz.  Under Device String, the field freq=7025e3 (7025 kHz = 7.025 MHz) and rate=625e2 (625E2 Hz = 62.5 kHz) are the only fields that have been changed.  Under LNB LO enter the tuned frequency RRI was at, in this example LNB LO = 7.025000 MHz.  Ensure the Audio Output settings are correct so that you'll be able to hear the audio.

Gqrx_instructions_settings.png

 

Selecting an RRI raw IQ file to play

Next, to load up an RRI raw IQ file, click on the Record and play I/Q data icon on the top toolbar (the icon looks liek a screen with a voltage trace).  In the Record and play I/Q data window, be sure to set your path to the audio file correctly.  When this is done, you see all of the files in the *.raw format.  You will then be able to select the file you want to play.

Gqrx_instructions_load.png

 

Playing an RRI raw IQ file

To play the selected file, hit Play in the I/Q recording and replay tool.  Ensure that Mode in the Receiver Options panel to the right is set on Raw I/Q.  Then select the Start DSP processing icon in the top toolbar (the icon looks like a traditional 'play' button).  The raw IQ audio file should start playing.  You should see a waterfall plot similar to the one shown below.  Notice that the  I/Q recording and replay toohas a timer and a slider which allows you to locate and reposition your place in the audio file.

Gqrx_instructions-play.png

 

If you have any comments, questions, or suggestions, please do not hesitate to contact Gareth Perry.