Problem with center tuning

[JMM8586]

Just upgraded my SDR# from V1500 To V1653. I have noticed that when I tune using center tuning rather then free tuning, I get significant interference and lower dBFS peak tuning to the same weatherband frequency. Its also apparent with other strong signals in my area. I am using RTL-SDR V3 dongles and they have been working great for the past year. Its only when I change the PPM settings to -1 to +1 that the signal comes in without interference, but the peaks do not line up with the waterfall. If I set the PPM back 0, and select free tuning, without any drift the signal is loud, clear, and strong only while the signal I am trying to listen to is to the right, or left of the center. I have gone back to using V1500. Any insight would be appreciated. Thank You!

 

[slicerwizard]

If no-one has any ideas, try making a video.

 

[putterizer]

Just upgraded my SDR# from V1500 To V1653. I have noticed that when I tune using center tuning rather then free tuning, I get significant interference and lower dBFS peak tuning to the same weatherband frequency. Its also apparent with other strong signals in my area. I am using RTL-SDR V3 dongles and they have been working great for the past year. Its only when I change the PPM settings to -1 to +1 that the signal comes in without interference, but the peaks do not line up with the waterfall. If I set the PPM back 0, and select free tuning, without any drift the signal is loud, clear, and strong only while the signal I am trying to listen to is to the right, or left of the center. I have gone back to using V1500. Any insight would be appreciated. Thank You!

I'm using SDR# 1631 and have this same exact issue. The peaks line up with waterfall, and there is interference with PPM at 0. If I offset the PPM to +10, the peaks dont line up, but my audio is coming in without any interference now. I have also tuned mine with weather channel, as well as a very strong local VHF channel from the local police dispatch.

 

[JMM8586]

ill try to make a video but since then I have went back to the old version. My sdr dongles are tuned correctly and they have never drifted at any point since new. If I keep the PPM at 0 where the peaks line up perfectly, the only way I get full strength signals is if I select free tuning and tune the strong active frequency either to the left or right of the center. Tuning center brings strong interference.

 

[DaveNF2G]

Do you mean actual "center tuning" or do you mean tuning your signal at the center of the display?

The infamous DC spike at the center of the spectrum display will cause distortion if you try to place your desired frequency there.

Another distortion creator is forgetting to offset the LO from the tuned frequency.

 

[DRL-XM43]

Do you mean actual "center tuning" or do you mean tuning your signal at the center of the display?

The infamous DC spike at the center of the spectrum display will cause distortion if you try to place your desired frequency there.

Another distortion creator is forgetting to offset the LO from the tuned frequency.

What DaveNF2G said!