Static Decoding NXDN48

[Neopacolipse]

I am running SDR# v. 1.0.0.1433 with an RTL receiver. Also running DSD+ 1.071 (Public Release May 2015)

Using Unfiltered audio from the virtual cable.

My issue is that when decoding the NXDN48 signal the voice audio is covered in static and almost indeterminable. This is only in the decoding. I have used 2 similar RTL receivers on 2 separate computers.

Below I have included a small log of what DSD+ decodes and displays while we were doing radio tests back and forth. There are no issues hearing the voice between either of the radios, only upon decoding using the SDR. The issue is also only with the digital decoding. The analog is clear as day when being received by the RTL's as well.

I assume the e is stating errors. is there a way to rectify this either in the decoding or in the programing of the NXDN (Kenwood NX-220 and Kenwood NX-700) radios. Any and all help is appreciated.

Sync:*NXDN48 CS VOICE e:1
Sync: no sync
Sync:*NXDN48 CS DATA
Sync:*NXDN48 CS DATA
Sync:*NXDN48 CS VOICE e:24r24r
Sync:*NXDN48 CS VOICE e:12
Sync:*NXDN48 CS VOICE e:6r122
Sync:*NXDN48 CS VOICE e:12
Sync:*NXDN48 CS VOICE e:124r
Sync:*NXDN48 CS VOICE e:315r2
Sync:*NXDN48 CS VOICE e:1214r
Sync:*NXDN48 CS VOICE e:211
Sync:*NXDN48 CS VOICE e:32
Sync:*NXDN48 CS VOICE e:1114r
Sync:*NXDN48 CS VOICE e:4r232
Sync:*NXDN48 CS VOICE e:11
Sync:*NXDN48 CS VOICE e:1221
Sync:*NXDN48 CS VOICE e:211
Sync:*NXDN48 CS VOICE e:122
Sync:*NXDN48 CS VOICE e:12
Sync:*NXDN48 CS VOICE e:2212
Sync:*NXDN48 CS VOICE e:3211
Sync:*NXDN48 CS VOICE e:24r

 

[mtindor]

Are the radios in close proximity and thus possibly/probably overloading the frontend of your receiver? If so,in SDR# makesure you lower the gain so that the signal fits into a 4khz or so bandwidth in SDR#, or is down to perhaps 30db above the noise.

And set your bandwidth in SDR# to something nice and minimal, I usually go with 4 khz. Makes a big difference in decode for me.

Lastly, you might need to follow the instructions in the DSDPlus.txt file for Advanced Tuning to eek more performance out via filter adjustment.

mike

 

[slicerwizard]

OP should try DSD+ 1.101 with TCP linked FMP. FMP bandwidth filter should be set to 4 kHz and PPM correction should be dialed in correctly. Don't dick with anything (FMP volume level, noise filters, ...)