DSD+ Need help:

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I've got DSD+ running with my RTL-SDR. Not sure if I've got it working right or not. When i switch the radio to NFM as the tutorial says to do, all goes silent. I notice if I put it on WFM that I hear noise. I've been trying to find frequencies to listen to all day long but none of them seem to cause the DSD+ window to start scrolling. Last line in DSD says "Mono audio decoding initiated;" nothing happens after that.
 
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Well, I've got the DSD+ decoding a signal and I see audio coming through the audio signal window that pops up when you start the program, but it seems that I cannot hear anything when it's working. If I tweak a couple settings, I can get sound back but the DSD+ stops decoding. I've spent about ten actual hours screwing with this thing and about to lose it. This is why I hate computers. They add a whole extra level of BS to have to contend with.
 

M105

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DSD+ Audio output should be to the speakers not back into the cable.
Turn off all audio filters in SDR# if you are decoding digital signals.
 

78turbo

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In the screenshot, the bandwidth is wide, and I believe Correct IQ should be checked. It also does not show any valid signal in the waterfall for DSD to decode. What antenna are you using? Is the SDR PPM set?
 

slicerwizard

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In the screenshot, the bandwidth is wide,
No, it's only 11 kHz.


and I believe Correct IQ should be checked.
It should, but not checking it wouldn't cause the OP's problem.


It also does not show any valid signal in the waterfall for DSD to decode. What antenna are you using? Is the SDR PPM set?
If it's not one of the good dongles with a nice TXCO, I'd bet on PPM...
 

mtindor

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The reason you weren't hearing "noise" on NFM is because you have "Squelch" checkmarked. Look at your screenshot. Squelch is inactive on WFM, which is why you do hear "noise" on WFM.

1. Uncheck "Squelch" under the Radio section
2. Uncheck "Filter Audio" under the Audio section

And, I think for dongles you either have to have "Correct IQ" or "Swap I and Q" checkmarked.

For the "Bandwidth" under the radio setting, you shouldn't need more than 10 khz set for P25, DMR, NXDN. In fact, you'll likely want even lower set for DMR and NXDN. I usually have it set to 10K for P25, 8K for DMR, and 8K or 4K for NXDN / IDAS (depending upon whether it's 9600 or 4800 NXDN).

Mike
 
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This is the device and antennas that I have. https://www.amazon.com/RTL-SDR-Blog...e=UTF8&qid=1494259271&sr=8-3&keywords=rtl-sdr
I downloaded the DSD+ plugin for SDR# and managed to get it to start decoding(the DSD+ window starts scrolling) and finally managed to get audio out of it. However, while decoding I fail to hear any voice whatsoever on any channel I selected, only noise. I parked about a block from the local police and fire stations and no signal I received was anything involving voice. I was surprised that no signal was particular strong. These are the frequencies I was watching https://www.radioreference.com /apps/db/?ctid=3024 , my location was Bluefield. The local FM station was strong.
 

mtindor

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Please forgive my ignorance on this - what exactly does "swap I and Q" do, and why is checking it so deleterious?

Max
I found this on the internet [and you know what that means].

Swap I & Q – Swap I & Q inputs. Useful when using sound card input devices Swaps L/R inputs to I/Q
I guess, as an example, you might tune to 7230 and have LSB checked [knowing the transmission is LSB] but yet you'r hearing USB. Swap the I &Q to fix, apparently.

Mike
 

slicerwizard

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Ok, so PPM errors are likely not an issue.


I downloaded the DSD+ plugin for SDR#
Yuck. DSD+ comes with its own dongle tuner (FMP or FMP24); it eliminates the need for virtual audio cables.


and managed to get it to start decoding(the DSD+ window starts scrolling) and finally managed to get audio out of it. However, while decoding I fail to hear any voice whatsoever on any channel I selected, only noise. I parked about a block from the local police and fire stations and no signal I received was anything involving voice.
I have my doubts that the police or fire repeaters are located at the stations. Repeaters are usually located on tall buildings or hilltops.


I was surprised that no signal was particular strong. These are the frequencies I was watching https://www.radioreference.com /apps/db/?ctid=3024 , my location was Bluefield. The local FM station was strong.
An analog dispatch channel is listed as 155.31; are you using a suitable VHF antenna? Or are you just monitoring DMR on 453.325? Again, with a suitable antenna? Is it outdoors? Have you maxed out the RF gain? Appropriate bandwidth selection would be 8 to 12 kHz.
 
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For those wanting to know the antenna I'm using, I posted a link to it in the above comments. Not being in town now, this is the best I can do as for signal strength. DSD menu scrolls information and I just hear static. I don't understand why I have to be at a repeater to get a signal. Shouldn't being in town be good close enough to pick up conversations?
 

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M105

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Are you are just sitting on the control channel? If so, you should hear nothing. You have to tune to the voice channels in the system to hear voice.

Did you set DSD+ audio output to the speakers?
 
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I don't know what control channels are, I didn't realize there were voice channels, I do have it set up as you asked, didn't know I had an old version of DSD+ it's what I downloaded from their site just the other day, I'm a noob and I'm about to throw this thing in the trash. screw it
 

M105

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Everybody is a "noob" to begin with. Put on your reading glasses and thinking cap. There is plenty of information out there. It ain't rocket science.
 
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