Defective 820T Dongle?

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iscri

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I recently bought a R820T dongle from NooElec and I seem to be encountering some weird issues:

I can tune fine and pick up various signals (FM stations, NOAA WX, Police, ATC etc) but randomly I get some sort of interference as shown in the attached screenshots. This interference isn't constant, sometimes it is present when I first fire the radio up and sometimes it just becomes present in various forms, across multiple bands over time.

When I unplug the antenna it goes away. Initially I thought I was overloading it with my vertical but the interference occurs with the included antenna, a telescopic whip, a dipole and a directional. I have also tried to tune the interference in on an Icom R-20 and a Uniden BC-246 and it isn't present.

I have tried playing with the gain (at 0 it still comes in at maximum strength on some bands), software settings, etc and I use a shielded USB extension with a ferrite choke on the end, tired other USB ports, remounted the board in a grounded aluminum case (also tried without the case) and while all this cut the noise floor the strange interference remains. I have also powered down all electronics other than the computer and the antennas are not near powerlines and my office is set back away from the houses near by. Also depending on what band I am in, I have to correct for drift which I expected but in some cases substantially... For example when tuning 162.400MHz I have to set the correction to -408 ppm but in the 800MHz band up it is dead on, not sure if this is related but it can't hurt mentioning it.

This kind of leads me to conclude I have a defective dongle but I figured I would ask first before returning it.

Thanks for any help.
 

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Arkmood

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Dec 19, 2002
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Taney County MO
-408ppm seems extreme and it should be uniform across the entire spectrum... sounds like you've taken most corrective measures...

One thing I'd try, (if you haven't yet) in SDR# config. uncheck RTL AGC/Tuner AGC and see if that helps. Otherwise send it back to NooElec.They're good about defective stuff, if the problem persists- you'll know it's on your end...
 
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