op25 (police radio)

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studysession
Posts: 5
Joined: Fri Aug 10, 2018 10:26 pm

op25 (police radio)

Post by studysession » Fri Oct 19, 2018 9:43 pm

Question about op25 -
Taken me couple of weeks to come this far. I believe I have the trunk.tsv & mycity.tsv file configured correctly. Anything I find online says I need to adjust the -q setting to get things working. I can never get the line over the peak of the frequency. Any help would be appreciated as I have tried many positive and negative numbers and not moved that line at all.

In the photos you you can see the syntax I have and what has been showing on my screen. I keep switching between the RTL-SDR & HackRF to see if there is anything different. Same result regardless which one I use.

THANK YOU :?:
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phil
Posts: 45
Joined: Mon Aug 21, 2017 11:02 pm

Re: op25 (police radio)

Post by phil » Sat Oct 20, 2018 2:24 am

It's been a few months since i used my op25, but from memory, there are keys (poss. the arrow keys) that allow for live fine tuning. Have you tried those in conjunction with the phase plot?

ScanCaster
Posts: 3
Joined: Sat Jul 22, 2017 7:27 am
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Re: op25 (police radio)

Post by ScanCaster » Sun Jan 06, 2019 8:55 pm

studysession wrote:
Fri Oct 19, 2018 9:43 pm
Question about op25 -
Taken me couple of weeks to come this far. I believe I have the trunk.tsv & mycity.tsv file configured correctly. Anything I find online says I need to adjust the -q setting to get things working. I can never get the line over the peak of the frequency. Any help would be appreciated as I have tried many positive and negative numbers and not moved that line at all.

In the photos you you can see the syntax I have and what has been showing on my screen. I keep switching between the RTL-SDR & HackRF to see if there is anything different. Same result regardless which one I use.

THANK YOU :?:
You are correct, the -q function is the PPM correction more commonly used as -p for most other RTL software... but thats OP25... they like to go against the grain.

The issue is YOUR COMMAND...

YOU have:

Code: Select all

./rx.py --args 'hackrf' --gains 'lna:49' -f 851.1625e6 -T newtrunk.tsv -S 1000000 -o 25000 -w 2>stderr.2 -q -2 

The issue is the -q 2 command is AFTER where it needs to be your passing it to the pipe of stderr, rx.py never get its so it never moves.

CHANGE TO;

Code: Select all

./rx.py --args 'hackrf' --gains 'lna:49' -f 851.1625e6  -q -2 -T newtrunk.tsv -S 1000000 -o 25000 -w 2>stderr.2 
You may have to play with it... I was under the understanding the hackrf's were far more stable and closer to spec v. the asian generic dongles... especially for something thats $200!

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