OP25 Pi3 and OP25 no audio from onboard jack

[jerry01]

I am able to get OP25 working I think, but I am not getting any audio from the onboard jack.

./rx.py --args 'rtl'-U -N 'LNA:47' -S 1440000 -f 774.46875 -T trunk.tsv -D fsk4 -V -2 2> stderr.2 -l http:127.0.0.1:8080


I get audio from youtube so that works , so kinda in the dark any hints?

 

[boatbod]

Fine tune offset -20400? That's most probably not correct; anything larger than +/- 350 usually means you need to adjust ppm (-q)

What makes you think you need -D fsk4? Given that you are in Orange Co NY, I'm willing to bet you are trying to receive Orange County Radio Network which is listed as a P25 Phase 2 system. Phase 2 is QPSK modulated not C4FM.

 

[jerry01]

Not sure I understand the offset, yes I am trying to get the new p25 our dept is now on it and trying to get division 1 and response 1

I have a orange.tsv setup in the trunk as follows
2002 West Response
2005 LE West Tac
2007 911 Priority
3001 EMS Response 1
3002 EMS Response 2
3003 EMS 4
3004 EMS 5
3005 EMS 6
3006 EMS 7
3007 EMS District 1
3008 EMS District 2
3009 EMS District 3
3010 EMS District 4
3011 EMS District 5
3012 EMS District 6
3013 EMS District 7
4001 FD Response 1
4002 FD Response 2
4003 FD Command 3
4004 FD Command 4
4005 FD Command 5
4006 FD Command 6
4007 FD Div 1
4008 FD Div 1 Tac
4009 FD Div 2
4010 FD Div 2 Tac
4011 FD Div 3
4012 FD Div 3 Tac
8683 Special Evnts 14
8684 Special Evnts 15
8685 Special Evnts 16
10101 System Techs 1
10102 System Techs 2
10103 DES 911
10104 Emerg Services
10105 EM 1
10110 HazMat Ops
10112 EM 2
10206 Special Evnts 1
10207 Special Evnts 2
10208 Special Evnts 3
10209 Special Evnts 4
10210 Special Evnts 5
10211Special Evnts 6
10212 Special Evnts 7
10213 Special Evnts 8
10214 Special Evnts 9
10215 Special Evnts 10
10216 Special Evnts 11
10217 Special Evnts 12
10218 Special Evnts 13
20101 4OCSO Patrol
20103 OCSO Tac 1
20104 OCSO Investigtrs
20107 OCSO SOG 1
20108 OCSO SOG 2
20109 OCSO SOG 3
20110 OCSO SOG 4
20201 OC D. A.
22301 Mt Hope PD Tac
22701 NYSP Dispatch
22702 NYSP Tac
24601 NYS DEC ECO Tac
60001 Interop 1
60002 Interop 2
60003 Interop 3
60004 Interop 4
60005 County Interop

 

[boatbod]

I suggest the following command line options as a starting point:
./rx.py -l http:127.0.0.1:8080 --args 'rtl' -N 'LNA:47' -S 960000 -q 0 -d 0 -T trunk.tsv -V -2 -U 2> stderr.2

Once you have the system running, open up a mixer plot and see if the signal peak looks centered. TSBK counter should be incrementing steadily. If not, the ppm (-q 0) and or fine tuning (-d 0) may need adjusting.

 

[jerry01]

@boatbod , ok so the pi 3 keep freezing so I built a laptop (atom processor) on ubuntu 16.04 got it all loaded and seems to be working, but like you said no more then 300 on q... currently says freq 852.775 (-1400). So my question is does the q move the -1400 down with a plus or minus. Not sure how to get in the parameters you said.

./rx.py --args 'rtl' -N 'LNA:47' -S 960000 -q 20 -d -100 -T trunk.tsv -V -2 -U 2> stderr.2

 

[kdttocs]

Pretty sure you need a -O parameter when you launch OP25. I haven't tackled sending audio to audio jack but when you send to a streaming server like blackice, you use "-O loop0"as a parameter. I recall seeing somewhere where you replace loop0 with something different to send to local audio output. If I find it I will update.

edit: I found the documentation on the Audio parameter option:
-O AUDIO_OUTPUT, --audio-output=AUDIO_OUTPUT pcm output device name. E.g., hw:0,0 or /dev/dsp

edit2: Try adding this: -O plughw:0,0

 

[boatbod]

@boatbod , ok so the pi 3 keep freezing so I built a laptop (atom processor) on ubuntu 16.04 got it all loaded and seems to be working, but like you said no more then 300 on q... currently says freq 852.775 (-1400). So my question is does the q move the -1400 down with a plus or minus. Not sure how to get in the parameters you said.

./rx.py --args 'rtl' -N 'LNA:47' -S 960000 -q 20 -d -100 -T trunk.tsv -V -2 -U 2> stderr.2

When a pi3 starts 'freezing' the first suspect is an inadequate power supply. Make sure you have one capable of the full 2.2A for micro-USB.

Best advice I can give for ppm adjustment is to tweak the -q parameter by +/-1 at a time and observe what happens to the signal peak in the mixer plot. If the peak moves the wrong way, go back and change the adjustment the other way. Theoretically the sign of the fine tune and ppm correction should be the same, but I won't swear to it, nor bet my paycheck on the expected outcome!

A 1400 fine tune correction probably translates to about 2 ppm at 700/800Mhz. Suggest you start with 1ppm and then go to 2 if needed.

 

[jerry01]

ok well i am using -q 23 -d 0 but seems the freq seems to move alot , I have to fine turn it when I see the tsbks stop incriminating. Runs good for a bit then stop I change it -100 or plus either way for it to start back up. Is there not auto tune or something once your close?

 

[boatbod]

ok well i am using -q 23 -d 0 but seems the freq seems to move alot , I have to fine turn it when I see the tsbks stop incriminating. Runs good for a bit then stop I change it -100 or plus either way for it to start back up. Is there not auto tune or something once your close?

23ppm (~16khz) is quite a lot of correction but not unheard of if you have an older non-temp compensated dongle. The modern TCXO dongles usually hold +/- 1ppm. The other issue is if you do have a non-compensated rtl, the frequency will drift significantly as the unit warms up when you first start op25. It is possible to manage this by adjusting fine tune, but obviously tedious and I really recommend getting better hardware for the $25 approx cost.

 

[jerry01]

@boatbod, I ordered one of these from amazon :
RTL-SDR Blog V3 R820T2 RTL2832U 1PPM