Digital Trunk Tracking Help

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Joined: Thu Jan 22, 2015 7:36 pm

Digital Trunk Tracking Help

Post by Tecnica » Thu Jan 22, 2015 10:58 pm

Hello everyone hoping that I can get some here.
I have X2 Nooelec r820t sdr & dvb-t nesdr mini dongles

I am trying to monitor this Trunk Radio System.
Nassau County Public Services (FL)

System Name: Nassau County Public Services (FL)
Location: Nassau County, FL
County: Nassau
System Type: Project 25 Phase I
System Voice: APCO-25 Common Air Interface Exclusive
Last Updated: February 3, 2012, 5:52 pm (Updated Sites)

System ID List
System ID WACN
1D5 BEE00

System Frequencies
Red (c) are primary control channels | Blue (a) are alternate control channels | Site Map(s): FCC Callsigns RR Locations

RFSS Site Name Freqs
1 (1) 001 (1) Simulcast 854.58750 855.71250 856.48750 857.26250c 857.48750a

I used SDR # to see which channel has the strongest signal and it looks like it's the alternate channel.

Now onto Unitrunker following the guide from this site.
I set up the #1 dongle to be the signal and dongle #2 to be the voice
I can verify that Dongle #1 is picking up the signal and is working.

However dongle #2 all I am hearing is static, nothing else
What am I doing wrong?

Screenshots are provided.
I thank you all ahead of time.


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Posts: 2410
Joined: Mon Nov 19, 2012 11:54 pm

Re: Digital Trunk Tracking Help

Post by rtlsdrblog » Fri Jan 23, 2015 10:57 am

Do both your dongles have the exact same PPM offset of 63? Check the PPM of the voice receiver and set it properly in Unitrunker. The PPM offset may be large enough so that you are receiving a few kHz off the voice frequency.

The new unitrunker also has a "drift correct" option which might help.

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