RTL-SDR.COM dongle Anodizing

[thewraith2008]

Applies to V2 and V3 dongles

Just thought I'd mention that the anodizing on the case of this dongles is non-conductive.

Sometimes the PCB and end plates make poor contact with the case potentially leading to unwanted signals or noise affecting the dongle.

In my case (no pun intended) I had no continuity between SMA connector and case.

A light file in the PCB guides, case ends and end plates (inside) fixed this.

Cheers

 

[moonbounce]

I have the V3 and when I place a lead of an ohm meter on the usb connector on the outside and the other lead on the case and I get an open circuit. Then if I move the lead on the case around I will get a closed circuit in some spots? Not quite sure what to make of that. You would think that the results would be all the same.

If I put the negative lead of the ohm meter on the anode of the antenna lead and the positive lead on the case the indicator will move but it doesn't show a closed circuit. I have not taken my dongle apart. I do see where the USB connector touches the case but and i am not sure but I think these points should be common ground right.

MB

 

[thewraith2008]

Then if I move the lead on the case around I will get a closed circuit in some spots?

The anodizing on the case is fairly thin. Moving lead around on case breaches this layer and closes circuit.

USB shield to SMA thread = Closed
USB shield to end plate screws = Closed

Disclaimer: Do the following at your own peril.

The only way to test the PCB ground making connection with the case is to remove nut off the SMA connector, remove screws from end plates and remove the plates, then test between USB shield and where a screw went in. Not the outside of the case. If closed circuit then sweet. Give it a wiggle while testing, see if it cuts the tone out or resistance changes.

I just lightly used a hacksaw blade to scourer the anodizing. I also re-soldered the both sides of PCB edges to make it a firmer fit.
I also sanded the inside of the plates and the mating edges of case.

Will all this make a difference. Maybe, Maybe not.

The sidebanding of strong signals in the V3 batch 1 is probably a bigger issue.

Cheers

 

[moonbounce]

Did all three test and happy to report all passed with flying colours

MB

 

[thewraith2008]

Good to hear. Doesn't hurt to try. And nothing to lose if your careful.

Cheers