Unitrunker + RTL + DSD+ = Poor Decode Rate

[Fizz306]

Hello all,

Not sure if this belongs here or in the DSD forum, but I'm assuming it goes here.

I love UniTrunker. I love DSDPlus. I love my RTL sticks. But in this configuration, using the most recent public Unitrunker release, they don't love eachother.

Stick one acts as a signal. Works great on the local NJICS system, and follows great. Stick two acts as the voice, controlled by Unitrunker to follow. Audio runs from VAC line 4 into Unitrunker with no issues, but the decode rate is terrible. Actually, I can't ever make out anything, not matter how much I fiddle.

Of note, I can get "reasonable" decode rates when using SDR #, Youssef filter, WFM with about 11.5kHz bandwidth.

Obviously, I can't tinker with how the signal is treated and filtered in Unitrunker prior to it heading over to DSDPlus. I've played with VAC Line 4's audio levels to no avail. I've also recorded RAW audio from the system using the r command in DSDPlus, and running it thorough DSDTune. The results are as follows, and actually makes the attempted decode even worse:

Wed Oct 08 21:07:17 2014 : Best Decode on file test.wav was 15435 with options -dr2 -dh8 -ds50 -dd39 -dv16

Screenshot attached below. Where am I going wrong here?

As always, I appreciate any help offered from this community.

 

[SCPD]

Hi Rob;

I'm looking at the waveform in the lower right corner of your screenshot.

The CQPSK waveform appears as shallow or tall peaks that may be positive or negative. From what I can see, the positive peaks look good. The negative "tall" peaks look okay. I don't see any shallow negative peaks.

That may mean your RTL stick is slightly off center. Try adjusting the voice RTL's correction value up or down by 1 (maybe 2).

 

[Fizz306]

Unitrunker,

Thanks for the reply. I've also been trying to configure the Unitrunker plugin for SDR# so that I can use Unitrunker to control the SDR# RTL stick, but haven't had any luck. It's a little easier for me to see where I'm on frequency when I have a waterfall and spectrum.

In regards to the comment:

"The CQPSK waveform appears as shallow or tall peaks that may be positive or negative. From what I can see, the positive peaks look good. The negative "tall" peaks look okay. I don't see any shallow negative peaks."

Would you happen to have a link to point me in a direction to learn a little more about these peaks, and how to read the waveform a little better?

I really appreciate your consideration and assistance, and thanks again for a really fun piece of software!

Rob

 

[SCPD]

On the signal receiver, you can bump the correction value up / down by 1, 2, 3 or more and flip to the 'scope tab to see the effects on the waveform. Starting with a centered CQPSK signal, try adding 2 and subtracting 2 to see the resulting waveform.

The waterfall display is nice to look at but a bit expensive in CPU. Some lower end hardware has trouble running Unitrunker, SDR#, and DSD or DSD+ all at once.

 

[Fizz306]

Unitrunker,

Thanks again for the insight. I'm looking forward to trying it out later tonight.

I just built out an AMD Computer and beef it up a little bit so that I could run as much as humanly possible when it comes to this type of software. So far so good. Maybe someday it'll be an option for a waterfall in Unitrunker.

All the best,

Rob

 

[joeuser]

Fizz? Have you updated to the latest version of DSD+?

 

[Fizz306]

I'm using 1.51. The one released last week. I've also tried with DSD160 as well.