Simple SDR programs for Linux using GNU Radio Companion

Here are a few simple SDR programs for Linux using GNU Radio and the GNU Radio Companion for use with the Sentinel 4 , SDR-4+ , Sentinel 2 and SoftRock receivers.

GNU Radio is a free software development toolkit available in Linux that provides signal processing blocks to implement software-defined radios and signal-processing systems. It can be used with external RF hardware to create software-defined radios, or without hardware in a simulation-like environment. It is widely used in hobbyist, academic, and commercial environments to support both wireless communications research and real-world radio systems.

The GNU Radio Companion is a graphical UI used to develop GNU Radio applications. This is the front-end to the GNU Radio libraries for signal processing. The sample files below open and run in GNU Radio Companion. The sample files can be inspected and changed to suit the users requirements.

If you have never used GNU Radio or GNU Radio Companion before download GNU Radio and all it's libraries from your Linux repository. Open GNU Radio Companion and select one of the sample files.

If you are using a Sentinel 4 , SDR-4+ , Sentinel 2 or SoftRock receiver go to Sound settings in Linux and select the audio sound card used by the receiver for input. Select your usual audio sound card for your loudspeakers for output.

When the sample files are run you should now see signals on the waterfall display and be able to tune around either side of the centre frequency using the slider control.

If you want to use the programs with WSJT-X or FlDigi then select the audio monitor for your loudspeaker sound card as your audio input. For the SDR-4+ and SoftRock receivers select "SoftRock Si570 AVR-USB" for CAT frequency control, for the Sentinel 2 select "Kenwood TS-570D" at 9600 bd and for the Sentinel 4 select "Kenwood TS-2000" at 19200 bd.

Sample files:

CW receiver A SDR receiver designed for CW use. It has three selectable filters 900 Hz, 500 Hz and 200 Hz wide centred on 700 Hz.

LSB receiver A SDR receiver designed for LSB use. It has three selectable filters 2500 Hz, 300 Hz for CW and 325 Hz for RTTY.

RTTY receiver A SDR receiver designed for RTTY use with another decoder program. It has three selectable filters 1700 Hz, 325 Hz and 200 Hz wide centred on the standard RTTY tone frequencies.

USB receiver A SDR receiver designed for USB and data use. It has three selectable filters 2500 Hz, 300 Hz for CW and 1000 Hz wide for use with HF APRS programs such as APRS Messenger.

WSPR receiver A SDR receiver designed for WSPR use with the WSJT-X program. It has a single filter 200 Hz wide centred on 1500 Hz. There is no frequency slider on this program. The screenshot at the top of this web page shows this program working with WSJT-X decoding WSPR signals with a Sentinel 2 receiver.

WSPR receiver with no display A SDR receiver designed for WSPR use with the WSJT-X program for use with an earlier low speed PC. It has a single filter 200 Hz wide centred on 1500 Hz. There is no frequency slider on this program just an audio output slider. The displays have been removed and decimation added to reduce the CPU use by almost half over the other WSPR receiver file above. This file can be used with old Windows XP era PCs updated with Xubuntu 18.04. I use this on two WSPR receivers I have running 24/7 with excellent results.

AM receiver A SDR receiver designed for AM broadcast reception. It has a 11 kHz wide filter for AM broadcast reception.

Note...All the files have been written and tested using the Ubuntu 18.04 LTS version of Linux. They may not work with earlier versions.

Special thanks must go to Ross Wilkinson, G6GVI who gave an interesting talk on GNU Radio Companion at the Bolton Wireless Club that opened up the possibilities to all who were there.

If you require more detailed information please contact us by email at info@crosscountrywireless.net