Andy,

Try formatting your rx.py command line as follows.

./rx.py --args ‘rtl’ --gains ‘lna:49’ -f 151.400e6 -S 2500000 -q 0 -T trunk.tsv -U -V 2> stderr.2

Note the formatting of the LNA gain setting for the RTL SDR device and you must either input the frequency in Hz or use the e6 notation to input MHz as you have done.  Your sample rate -S 2500000 need not be set so high but should work fine on VirtualBox.  This would place too high of a demand on the CPU on the Raspberry Pi where -S 1000000 works well.

You may need to adjust the value for -q frequency correction once you can successfully start op25 (rx.py) without errors.   Observe the tsbks in the console screen once rx.py starts and adjust the value as needed to get the SDR dialed in to where it begins to decode trunk signaling blocks on the systems control channel.   It is normal that the tsbks counter halts as op25 follows a voice trunk but should resume upon return to the control channel frequency.

You can also skip the -f 151.400e6 on your rx.py command line if you are using Graham’s boatbod version.    Either way, you do need to specify the control channel and alternates in trunk.tsv.

Bill, WA8WG