A collection of tools, programs, and scripts to experiment with the SDRplay RSPduo in dual tuner mode

A simple C program that records to two files the I/Q streams for the A and B channels from an RSPduo in dual tuner mode; sample rate, decimation, IF frequency, IF bandwidth, gains, and center frequency are provided via command line arguments (see below).

To build it run these commands:

mkdir build
cd build
cmake ..
make (or ninja)

These are the command line options for dual_tuner_recorder:

-s <serial number>
-r <RSPduo sample rate>
-d <decimation>
-i <IF frequency>
-b <IF bandwidth>
-g <IF gain reduction> ("AGC" to enable AGC)
-l <LNA state>
-D disable post tuner DC offset compensation (default: enabled)
-I disable post tuner I/Q balance compensation (default: enabled)
-y tuner DC offset compensation parameters <dcCal,speedUp,trackTime,refeshRateTime> (default: 3,0,1,2048)
-f <center frequency>
-x <streaming time (s)> (default: 10s)
-o <output file> ('%c' will be replaced by the channel id (A or B) and 'SAMPLERATE' will be replaced by the estimated sample rate in kHz)

Here are some usage examples:

• record local NOAA weather radio on 162.55MHz using an RSPduo sample rate of 6MHz and IF=1620kHz:

./dual_tuner_recorder -r 6000000 -i 1620 -b 1536 -l 3 -f 162550000 -o noaa-6M-SAMPLERATEk-%c.iq16

• record local NOAA weather radio on 162.55MHz using an RSPduo sample rate of 8MHz and IF=2048kHz:

./dual_tuner_recorder -r 8000000 -i 2048 -b 1536 -l 3 -f 162550000 -o noaa-8M-SAMPLERATEk-%c.iq16

A simple Python script that demodulates a file containing an I/Q stream contaning a NBFM signal (see dual_tuner_recorder above) and shows a frequency plot of the I/Q stream. This script uses GNU Radio blocks and therefore requires a recent version of GNU Radio to run.

These are the command line options for fm_player:

-i <input file> - mandatory
-s <sample rate> - mandatory
-o <frequency offset> - default: 0
-N (FM block: NBFM receive)
-D (FM block: FM demod)
-v <volume> - default: 0.3
-f <center frequency for frequency display> - default: 0
-W (wait for user input) - default: False

Here are some usage examples:

• play the I/Q stream for channel A from the first example above (please note that the estimated sample rate in the file name might be slightly different; for instance in my case it was 'noaa-6M-2002k-A.iq16'; you may still want to use the command line option -s 2e6):

./fm_player.py -i noaa-6M-2000k-A.iq16 -s 2e6 -f 162550000

• play the I/Q stream for channel B from the second example above (see note in the previous example about the I/Q stream recording file name):

./fm_player.py -i noaa-8M-2000k-B.iq16 -s 2e6 -f 162550000

(C) 2022 Franco Venturi - Licensed under the GNU GPL V3 (see LICENSE)