DSD, SDR# and Unitrunker

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Envoys

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Just got a quick question, how come I can get better INLVL and a better decode using SDR#?

I have unitrunker setup using 2 RTL dongles, if I have SDR# follow the conversations the INLVL is around 55% and decodes are great. If i use unitrunker, the INLVL is at max 25-30% and the decodes are terrible, sputtering off and on. I would definitely prefer using Unitrunker as the CPU usage is next to nothing but using Unitrunker, SDR# and DSD all wreak havoc on the PC, the decodes work great but the PC can't do anything else.

If anyone has any thought, that would be great, thanks.
 

joeuser

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I'm guessing's its a gain setting in SDR# & you dont have it set or it needs adjusting in UT? I dont use SDR# anymore, just UT & the dongles.
 

Envoys

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Its a Motorola smartzone system so DSD won't decode it like a p25 system...although maybe I'm wrong about this?

As for the gain it seems no matter what I do in UT the inlvl for DSD never changes am I missing something? I have all windows settings 100% level.
 

SCPD

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Let me rephase that. What's the decode rate reported in Unitrunker on the signal receiver while tuned to a control channel?
 

Envoys

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Also on a side note, another issue, if I use unitrunker stand alone, some times the p25 digital is just sending the digital noise, dsd is not processing it. Then it will process the next call, this is hit or miss, depends on the delay between the calls being keyed up. It almost seems like the digital is being pushed out the analog path. I shut off DSD and it still does it.
 
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SCPD

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On a mixed analog / digital Motorola system - the initial call grant tells you whether the call is analog or digital. If you miss the grant message, the late entry messages tell you there's a call but not what type.

Under this circumstance, the only way to know a call is digital is to examine the voice channel.

There's a fix planned for this - but that is some time away.
 

Envoys

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Sounds good. It seems to only happen in the preview builds it doesn't seem to happen in the latest official one.

Any ideas on my original issue with the low DSD inlvl? Is there no place to adjust the AF gain?
 

SCPD

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There is no level adjustment on the discriminator audio passed through the program (and no plans to include one). I think the problem is the filtering inside DSD. Sourcing the audio from SDR# allows you compensate for this. That's just a guess.

Have you tried DSD+ ?
 

Envoys

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Yeah, same results with DSD+.

It's not horrible to use it this way, I love the feature of analog and digital separate outputs, just wish I could achieve a better decode rate in DSD/DSD+ using UT. Are there any other things I could do to improve it?
 

nlurker

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Envoy, I also get terrible voice decode with UT, and great voice decode with SDR#. But I think my problem is opposite from yours - the UT gain is too high (and not adjustable) and the SDR# gain is turned down low. If I turn the SDR# gain up as high as UT, I get the same terrible decode.
 

Envoys

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Interesting. I find it odd that I can mute the VB cable and decode still has the same level of 25-30%. I am going to research this a bit more. The volume levels used to affect the inlvl when I was using xp before but not since going to windows 7. I even thought maybe the PC was to slow so I got an i5 with 8gb ram and still the exact same issue. Its not horrible just seems the beginning is more likely to get errors and cut out. The middle and the end still stutters at times but not as bad as the beginning.
 

nlurker

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Envoy, I also found that the volume/mute controls on VB-cable have no effect on my win7. Please let me know if your research finds anything new. I am getting excellent results now using SDR#, but I would like to reduce the number of programs running if I can. My current setup is Unitrunker, SDR#, DSD+, and RadioFeed.
 

Envoys

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Weird... it appears the levels tab when under recording devices properties has no affect on the actual volume level but when I click the speaker bottom right and then click more and choose cable input and drag the slider for unitrunker "Site 23" all the way down, it will affect the decoding inlvl but it seems that it maxes out at 30-35%.

Maybe Unitrunker can shed some light on how the digital audio pipeline is passed to DSD? Is UT fixed at these levels? I have tried on 3 different PC's and all the same inlvl for dsd. Does it go based on signal quality etc? I don't remember having this issue in the previous versions before the separate digital output controls.
 

nlurker

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Envoys, thank you! That method of adjusting the gain works for me too! I turned down UT and am now getting legible voice decode for the first time.

UT is still not as good as SDR#, but much better than it was. It sounds like the very beginning of most transmissions gets garbled, like it is not locking onto the signal fast enough. That doesn't happen with SDR#. I will play with it and see if I can improve it further.
 

nlurker

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I think the beginning garble is related to tuner auto-gain. It seems to improve when I turn that off. But then I am having a difficult time setting the tuner gain optimally. Is there a better procedure than trial and error? Is there a signal strength meter like in SDR#?
 
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