EDACS beeps Unitrunker

First off, Unitrunker is brilliant and I love it. Thank you to the author and everyone's awesome posts to this forum that allowed me to get a fully functioning SDR scanner working on the Denver PD EDACS system. I owe you all one!

The one thing I haven't figured out is how to suppress the 5 trailing beeps after each call. It was a long debated feature, which according to the release notes for Unitrunker 29 was implemented. However, I hear the beeps after each call and can't find a setting anywhere to change that. What am I missing? Thanks for the help!

Turn on deemphasis. That should take care of the beeps.

EdmontonFireRadio said:

Turn on deemphasis. That should take care of the beeps.

Click to expand...

This. Thank you sir. Worked beautifully... surprised I hadn't tried that before. I owe you one now also!

Howdy,

I am experiencing the same issue as the original poster. "Deemphasis" under the "Voice" header is "X"ed on all of the voice VCO's, and I still get the beeps at the end of the transmission. See the end of this post for a screenshot of the VCO settings.

Here's an audio sample (a quick keyup followed by the "beeps" -- which sound more like surges or swooshing on the SDR): https://dl.dropboxusercontent.com/u/14976381/EDACS EOT Beeps UniTrunker.mp3

Are there other settings I should play with to try to end reception of the transmission before the beeps?

My SDR setup:

I have a R820T2 receiver setup in Unitrunker with 4 VCOs (1 signal, 2 analog voice, 1 analog/provoice voice). The Provoice VCO is fed to DSDPlus, and finally, the three voice feeds are routed to Trunking Recorder with VB virtual audio cables.

R208T2 ---> Unitrunker ---> 4 VCO:

VCO 1: Signal, no output
VCO 2: Analog voice ----> VB Cable A ---> Trunking Recorder
VCO 3: Analog voice ----> VB Cable ---> Trunking Recorder
VCO 4: Digital voice ----> VB Cable B ---> DSDPlus ---> Speaker Output ---> Trunking Recorder
VCO 4: Analog voice ----> Speaker Output ---> Trunking Recorder

(The provoice recordings have a couple of seconds of silence at the end; I assume the beeps are also sent to DSDPlus.)

Since I have the recording setup and running this afternoon during the busy call time , I've noticed I can get pretty far behind real time playing the recordings back to back with "Continuous playback" and "Auto play new calls" in Trunking Recorder. So besides settling the nerves, another practical reason for eliminating the beeps is to save a couple seconds at the end of each transmission to avoid too much backlog of unheard calls.

I've been scanning with a WS1080 for a couple of months, and I just started with SDR last week. I agree with YesApostrophe's praise: These software packages for trunking, decoding, and recording are awesome. I'm really pleased with my SDR setup, and I'm happy to help others duplicate what I did.

This is my first post on RR, so I must thank everyone for building such a great community and offering so much information and instruction, especially Mr. Blanton, Unitrunker, EricCarlson, Voyager, and everyone else who has helped me learn about scanning by asking questions (so I don't have to), updating databases, and contributing content to forums/wikis. I really do appreciate it, and I hope I can get to know many of you.

Cordially,

Justin

(Image full resolution link: https://dl.dropboxusercontent.com/u/14976381/VoiceVCOSettings.JPG)

AggieCon said:

Here's an audio sample (a quick keyup followed by the "beeps" -- which sound more like surges or swooshing on the SDR):

Click to expand...

I am still getting that same noise periodically as well. I think it might be a result of poor reception in my case; when I have a strong signal, the extra time at the end of the transmission is completely cut. The worse the voice signal, the more I can hear of the attenuated beeps / whooshes at the end.

If you want to hear the beeps completely unattenuated, try unchecking the deemphasis box on one of those analog voice channels. I could hear them across the room from headphones at 10% volume. Should give you an idea of what Unitrunker is doing to them.

As for the timing issue with recording, you are way ahead of me there.

Unitrunker is dampening the trailing tones, for sure. However, it's not truncating the transmission before the beeps as does my WS1080. From time to time, especially when I was setting things up, I listen to the voice frequencies in conventional non-trunking mode, so I am aware of how the beeps sound without any modification.

My question is whether there is some setting to tweak in Universal Trunker to stop the trailing beeps, or if it is just part of the ball game for now. Since my scanner can do it, I figure it is technologically possible. Also, I thought Unitrunker decoded the data stream to determine when to end the transmission (as opposed to audio drop off), which would be before the beeps, but perhaps I am incorrect.

There are no "end of transmission" messages sent on the control channel. To mute the beeps, a program would have to analyze the voice channel audio and detect the 4.8 kHz dotting sequences.

That's a good idea. I will play around with filters and see if I can find anything that silences it, if I can't remove it...

Forgive my lack of technical speaking. The control channel sends the initial go ahead for the call and continues to send a "continuation" message while the transmission is in progress (I assume this is for late entry). So the "end of transmission" message is really a lack of any other instruction.

I believe there is a low bitrate data stream with the voice channel, which is what instructs user radios to return to the control channel -- as well as send any higher priority call information or emergency calls. Does UniTrunker decode those messages?

IIRC from *many* years ago, there is low speed data present during voice traffic and it stops when the beeps start, so a simple detection of low frequency (0-300 Hz) content going away would be the trigger to drop the channel or at least mute it.

I know this post is late, but here is my take on the issue.

1. On regular scanners such as BC-996 etc, the 1st 4k beep tells the scanner to park.
2. Unitrunker doesn't understand that. (unfortunately)

What happens here is that the edacs 4k beep means nothing to unitrunker and as a result it will sit on that frequency until the 5 beeps are finished. And during that time, if the repeater sends something to that channel (say something like provoice) that digital garbage will come thru on the analog side, which is annoying.

If unitrunker would simply follow the same analogy as regular trunk tracking scanners that scan edacs systems, the problem would go away.

VA3JPX said:

I know this post is late, but here is my take on the issue.

1. On regular scanners such as BC-996 etc, the 1st 4k beep tells the scanner to park.
2. Unitrunker doesn't understand that. (unfortunately)

What happens here is that the edacs 4k beep means nothing to unitrunker and as a result it will sit on that frequency until the 5 beeps are finished. And during that time, if the repeater sends something to that channel (say something like provoice) that digital garbage will come thru on the analog side, which is annoying.

If unitrunker would simply follow the same analogy as regular trunk tracking scanners that scan edacs systems, the problem would go away.

Click to expand...

That is one of the issues being worked on in the Version 2 of Unitrunker. You can follow its development at the Unitrunker google group.

Thank you!

James
VA3JPX