DSD+ Fastlane - Unlocking Potential?

[slicerwizard]

Your dongle is off-frequency. You need to adjust the PPM correction in FMP24 until tuning to 851.150 actually puts the dongle squarely on that control channel signal. You need a correction value of about -35 PPM.

 

[jacky1mcc]

Your dongle is off-frequency. You need to adjust the PPM correction in FMP24 until tuning to 851.150 actually puts the dongle squarely on that control channel signal. You need a correction value of about -35 PPM.

I changed the -P for FMP24 to 28 and found that the control channel is locking on to 851.150 and hoping to the voice channels as directed. This setting also provides for the best audio quality. However the audio is still mostly distorted and only people with low volume voices can be understood. From my TV engineering background it looks like either there is insufficient bandwidth some where in the IF or audio chain or the audio entering or leaving DSD+ is to high. I tried changing the -b in the bat file to 15 from 12.5 and I don't see any change. In the header of the FMP24 spectrum display the BW indicates 9.5 when on the control channel and 12.5 on the voice channels. Changing to -b15 had no change in the audio quality or what is indicated on the spectrum header. Do you have any thoughts about this? Thanks for your assistance.

 

[DRL-XM43]

Deleted

 

[slicerwizard]

Playing with the RF bandwidth isn't going to change audio levels.

What does your DSD+ command line look like?

 

[jacky1mcc]

Thanks for your reply. Here is the contents from my start batch file. The batch file is from a previous response by DRL-XM43.

Start FMP24 -i1 -o20002 -f851.150 -b12.5 -P33 -q1 -g40 -_1 -wsl000.00
Start "" /AboveNormal DSDPlus -F1 -r1 -e -m1 -i20002 -OM NUL -_3

I don't understand the first part of line 2 "" /AboveNormal, I know the line starts and sets up DSD+.
I may be expecting to much for the quality of audio coming from this configuration.
I am able to understand most of the conversations coming from the speaker but I was expecting to have the quality coming from my Ham radio DMR HT. I was hoping that opening the RF BW up to 15 would pass more of the digital signal. but the highest BW appears to be 12.5.

Amazon just delivered a second SDR dongle to me and now I can play with the 2 dongle configuration. Thanks for your response.

 

[DRL-XM43]

Thanks for your reply. Here is the contents from my start batch file. The batch file is from a previous response by DRL-XM43.

Start FMP24 -i1 -o20002 -f851.150 -b12.5 -P33 -q1 -g40 -_1 -wsl000.00
Start "" /AboveNormal DSDPlus -F1 -r1 -e -m1 -i20002 -OM NUL -_3

I don't understand the first part of line 2 "" /AboveNormal, I know the line starts and sets up DSD+.
I may be expecting to much for the quality of audio coming from this configuration.
I am able to understand most of the conversations coming from the speaker but I was expecting to have the quality coming from my Ham radio DMR HT. I was hoping that opening the RF BW up to 15 would pass more of the digital signal. but the highest BW appears to be 12.5.

Amazon just delivered a second SDR dongle to me and now I can play with the 2 dongle configuration. Thanks for your response.

Theoretically "" /AboveNormal would afford DSD+ higher CPU priority. Removing it is no problem.

Start FMP24 -i1 -o20002 -f851.150 -b12.5 -P33 -q1 -g40 -_1 -wsl000.00
Start DSDPlus -F1 -r1 -e -m1 -i20002 -OM NUL -_3

Sometimes poor audio can be related to a USB cable issue (if used).

What level of signal are you receiving? Which trunk are you decoding?

 

[jacky1mcc]

I hear no difference plugging the dongle directly into the usb port on the computer or using a short USB extension. My primary site to monitor is the TXWarn Friendswood site but have connected to other local sites with no change in audio quality. I am not sure what my exact received signal level is but -g40 setting the peak is full 3/4 scale on the FPM24 spectrum display. I have tried several setting of the -g option with no effect on the audio quality. I have even tried putting the antenna on the floor to see id by chance I was overloading the front end of the SDR. Using the SDR the I just received in place my first SDR produces audio of about the same quality. When someone talks with a low voice level the audio sounds a lot better.

 

[jacky1mcc]

I hear no difference plugging the dongle directly into the usb port on the computer or using a short USB extension. My primary site to monitor is the TXWarn Friendswood site but have connected to other local sites with no change in audio quality. I am not sure what my exact received signal level is but -g40 setting the peak is full 3/4 scale on the FPM24 spectrum display. I have tried several setting of the -g option with no effect on the audio quality. I have even tried putting the antenna on the floor to see id by chance I was overloading the front end of the SDR. Using the SDR the I just received in place my first SDR produces audio of about the same quality. When someone talks with a low voice level the audio sounds a lot better.

Just tried changing to a USB3 port with no improvement.

 

[jacky1mcc]

Just tried changing to a USB3 port with no improvement.

I found that adding the audio output level for DSD+ -g and setting it for -g10 helps the quality of the audio but still not as good as my DMR-HT.

 

[LD723]

I hear no difference plugging the dongle directly into the usb port on the computer or using a short USB extension. My primary site to monitor is the TXWarn Friendswood site but have connected to other local sites with no change in audio quality. I am not sure what my exact received signal level is but -g40 setting the peak is full 3/4 scale on the FPM24 spectrum display. I have tried several setting of the -g option with no effect on the audio quality. I have even tried putting the antenna on the floor to see id by chance I was overloading the front end of the SDR. Using the SDR the I just received in place my first SDR produces audio of about the same quality. When someone talks with a low voice level the audio sounds a lot better.

It may just be because dsdplus does not use as good of a vocoder compared to an actual hardware scanner or an actual digital ht. I wish that one day dsdplus will update their vocoder. I've always wanted them to so the voice quality can sound soo much better on most or all digital modes

 

[jacky1mcc]

I suspected that I was wishing for too much. This will work until I can afford a SDS-200. for the most art I just want to monitor 3 sites. After playing with the -v setting in FMP2 and the -g setting in DSD+ I have got rid of some of the clipping in the audio. I is kind of working with SSB in the early days. THanks