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Posted: Thu Jan 31, 2019 6:29 pm
by w1dth
Hi, I could really use some help getting this to work. I had it working at one time but my decodes are garbled and sound like robots. It's not understandable at all. I thought it was computer power so I just updated to a newer computer and it is still bad.

Here's the setup.
Intel i3 3300 mhz dual core
4 gigs ram
VB Cable A and B
DSD+ lastest fast lane

SDR# scans between 2 frequencies.
Audio to DSD+ through VB Cable A
Audio going into DSD+ and I see it on the wave form
Audio from DSD+ though VB Cable B to RadioFeed for Broadcastify.

All the audio routing is correct because I am getting the crap sound coming from Broadcastify and I am seeing the talkgroup and radio ID in DSD+. I have all the audio filters turned off in SDR#. Squelch is off as well. AGC is off on the SDR. RF Gain is 3/4 max. Audio level in SDR# is 3/4 max but have had it all over the place trying to get it to work. Sound level for VB cables is both 100% on sound and mic settings in Windows 10.

I've been playing with this for so long.... Months! I have read everything I can on the net. This thing should be working but it's not. I'm ready to drop $400 and buy a HomePatrol and be done with it.


Posted: Fri Feb 01, 2019 7:27 pm
by Corrosive
You are running into one if not two problems here.

1) The P25 frequency are are listening to is likely on a system and hops around a lot as you are not following the control chanell. This can result in being able to hear something one moment and then nothing the next.

2) The frequency you are listening to is encrypted in which case it will sound garbled.

My suggestion is to either use Unitrunker (you'll need two RTL) or SDRTrunk which can track a system even with just 1 RTL-SDR. Unfortunately I have not yet made my tutorial on setting it up but it shouldn't be too bad.

SDRTrunk can be found here and you'll need the AMBE codec as well:


Posted: Sat Feb 02, 2019 12:27 am
by w1dth
Thanks for the suggestions but it is not a trunking system.

There are encrypted radios on the system but only some of the Sergeants use the encryption. DSD+ says ENC Group Call when they are using it and there is no audio at all then.


Posted: Sun Feb 03, 2019 3:02 pm
by w1dth
Fixed it.

Reduced volume to virtually completely off and it cleaned up.