It appears that you're trying to monitor a Motorola Type II SmartZone
system. op25 doesn't do that. It only does P25 and some DMR.
~iain
On Tue, Apr 14, 2020 at 10:19 AM Louis Wilen <[email protected]> wrote:
>
> I am in Montgomery County, MD trying to use OP25 to monitor the police and
> fire system.
>
> The platform is a Raspberry Pi 3b with the OS and all known drivers
> up-to-date.
>
> GQRX hears and shows a strong signal on the primary control channel
> frequency, 853.8625. GQRX also shows a strong signal on alternate control
> channel 853.6875. (I got the control channels from RadioReference.com.)
>
> Also, I can turn in local FM, VHF ham radio, etc. stations reliably with
> GQRX. The audio is excellent. So my dongle appears to be fine.
>
> Using a standalone scanner, I’ve verified the primary control channel
> frequency is what I have specified as the current control channel, 853.8625.
>
> I’m trying to find the NAC by running:
>
> ./rx.py –args “rtl” -N ‘LNA:47’ -S 2400000 -f 853.8625e6 2>stderr.2
>
> And that gives nothing on the OP25 console screen except “Frequency
> 853.862500(0)” in the bottom left corner. This should give me the NAC and
> other info in the upper left of the screen, but that area is blank.
>
> Even though I know the control channel is on 853.8625 (based on my standalone
> scanner), I figured that I'd try the above command but specify the alternate,
> 853.6875e6, as the control channel frequency. That gives me the following in
> the upper left corner:
>
> NAC 0x8e2 WACN 0xbee00 SYSID 0x8e0 853.687500/808.687500 tsbks 114
>
> That looks sort of good. But if I then use the secondary control channel and
> NAC 0x8E2 in the trunk.tsv file, the OP25 console screen still does not show
> any voice activity.
>
> The OP25 spectrum plot (option 1 plot) does show the peak for the control
> channel that I’ve selected.
>
> And I still don’t know why I can’t get the NAC or any meaningful OP25 console
> data for the primary control channel to appear since I know it’s the control
> channel that is in use, based on watching my standalone scanner.
>
> The stderr file does not show anything that seems abnormal. Here it is when
> specifying the primary control channel in the rx.py command line:
>
> —————————————————-
>
> gr-osmosdr 0.1.4 (0.1.4) gnuradio 3.7.13.4
>
> built-in source types: file osmosdr fcd rtl rtl_tcp uhd miri hackrf bladerf
> rfspace airspy airspyhf soapy redpitaya freesrp
>
> Using device #0 Realtek RTL2838UHIDIR SN: 00000001
>
> Found Rafael Micro R820T tuner
>
> [R82XX] PLL not locked!
>
> [R82XX] PLL not locked!
>
> Using two-stage decimator for speed=2400000, decim=25/4 if1=96000 if2=24000
>
> Project 25 IMBE Encoder/Decoder Fixed-Point implementation
>
> Developed by Pavel Yazev E-mail: [email protected]
>
> Version 1.0 (c) Copyright 2009
>
> This program comes with ABSOLUTELY NO WARRANTY.
>
> This is free software, and you are welcome to redistribute it
>
> under certain conditions; see the file “LICENSE” for details.
>
> p25_frame_assembler_impl: do_imbe[0], do_output[0], do_audio_output[0],
> do_phase2_tdma[0], do_nocrypt[0]
>
> metadata update not enabled
>
> Allocating 15 zero-copy buffers
>
> Flowgraph completed. Exiting
>
> —————————————————-
>
> My dongle is very stable and appears to be 'on frequency'. Still, I've tried
> using offsets and changing the frequency a bit to no avail.
>
> So what I’m mainly looking for is the NAC for the system at this point. Once
> I get that to appear on the screen when specifying the primary control
> channel on the command line, everything else should hopefully fall into place.
>
> Any suggestions would be appreciated.
>
> Louis
> W3VVV
>
>
