rpdale
commented
5 years ago Disregard- I ran gqrx again and I had the wrong box checked and was measuring the error on the same SDR both times :) Made sure to select S/N 2 and found the error was -32000 and not +750.
I have the system running on one SDR monitoring 800MHz channels at https://openmhz.com/system/mpscs
On the MPSCS tower of interest, the 700MHz freqs are 769.70625 | 770.70625 | 771.38125
I added a second SDR with this info (matching serial number 1 other than the error rate based on gqrx)
{ "sources": [{ "center": 852362500.0, "rate": 2400000.0, "error": 1000, "gain": 47, "driver": "osmosdr", "device": "rtl=1", "modulation": "fsk4", "digitalRecorders": 5 }, { "center": 770500000.0, "rate": 2400000.0, "error": 700, "gain": 47, "driver": "osmosdr", "device": "rtl=2", "modulation": "fsk4", "digitalRecorders": 2 }],
[2019-08-13 20:11:43.194257] (info) Source Device: rtl=2 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 #1 Realtek RTL2838UHIDIR SN: 2 Found Rafael Micro R820T tuner [R82XX] PLL not locked! [2019-08-13 20:11:43.814402] (info) SOURCE TYPE OSMOSDR (osmosdr) [2019-08-13 20:11:43.814539] (info) Setting sample rate to: 2400000 [R82XX] PLL not locked! [2019-08-13 20:11:43.930738] (info) Actual sample rate: 2400000 [2019-08-13 20:11:43.930959] (info) Tunning to 7.705007e+08 [2019-08-13 20:11:43.981475] (info) Gain Stage: LNA supported values: 0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48 49.6 [2019-08-13 20:11:43.981634] (info) Max Freqency: 7.717000e+08 [2019-08-13 20:11:43.981758] (info) Min Freqency: 7.693000e+08 [2019-08-13 20:11:44.006994] (info) LNA Gain set to: 0 [2019-08-13 20:11:44.032111] (info) TIA Gain set to: 0 [2019-08-13 20:11:44.057394] (info) PGA Gain set to: 0 [2019-08-13 20:11:44.082630] (info) Gain set to: 48 [2019-08-13 20:11:44.082818] (info) Setting antenna to [RX] [2019-08-13 20:11:44.139452] (info) P25 Recorder Initial Rate: 480000 Resampled Rate: 30000 Initial Decimation: 5 Decimation: 16 System Rate: 30000 ARB Rate: 1 [2019-08-13 20:11:44.139658] (info) P25 Recorder Taps - initial: 363 channel: 1455 ARB: 727 Total: 2545 [2019-08-13 20:11:44.202092] (info) P25 Recorder Initial Rate: 480000 Resampled Rate: 30000 Initial Decimation: 5 Decimation: 16 System Rate: 30000 ARB Rate: 1 [2019-08-13 20:11:44.202301] (info) P25 Recorder Taps - initial: 363 channel: 1455 ARB: 727 Total: 2545 [2019-08-13 20:11:44.226215] (info)
It is monitoring the 700MHz channels but here is the output:
[2019-08-13 21:44:52.887407] (info) [mpscs] TG: 2171 Freq: 7.707062e+08 Starting Recorder on Src: rtl=2
[2019-08-13 21:45:01.007503] (info) [mpscs] TG: 2171 Freq: 7.707062e+08 Ending Recorded Call - Last Update: 4s Call Elapsed: 9
[2019-08-13 21:45:01.008568] (info) - Stopping P25 Recorder Num [5] TG: 2171 Freq: 7.707062e+08 TDMA: false Slot: 0
[2019-08-13 21:45:01.009421] (info) [mpscs] Deleting this call as it has a duration less than minimum duration of 0 TG: 2171 Freq: 7.707062e+08 Call Duration: 0s
It's recording the call just fine (?) and then when the call completes, it is being deleted because the call duration 0 seconds long. All 700MHz frequencies show up this way.