It's all about the Software

Hallo, Ich verwende RTL-SDR 820T2 mit vorgeschaltetem Up- Converter und 6- Fach Bandfilter an einer FD4 Antenne

Das Problem ist, ich habe z.b. im 80m Band mehrere Stöhr quellen ca. 3 Khz breit (knarren und kratzen)
Ohne Antenne sind die Signale weg. An meinem ic-7300 sind an den Stellen keine Signale. Nun Ist der rRTL-SDR je Spitzengerät und man denkt zuerst an Kreuzmodulation oder Übersteuerung.

Merkwürdig ist aber, das die Störungen im SDR-Sharp nicht sind. (Also gar nicht !!!! )

Hat jemand eine Idee ?

Vielleicht falscher Treiber ?

73 de DJ2WW Lothar aus Gelsenkirchen

Try using a good quality USB cable. Or check the continuity of the ground (metal shield of the ends) with a DMM.
I had one that was open, and the spectrum was covered with USB RFI, more noticeable without an antenna connected.

73 Kriss KA1GJU

Hello Kriss,
When I read your answer, I immediately thought, "That can't be, then the disturbances would also be in SDR-Sharp."
But of course I tried it and plugged the RTL stick directly into the PC without an extension.
And ... disturbances disappeared. .-)
Thank you very much

Grüß Gott,

USB cables make great antennas, especially when the SDR is not well shielded. Ethernet cables can also radiate, I use FT240-31 cores on my problematic cables out in the repeater shed to reduce QRM on my 4 SDR's running as a server out there.

By the way...
My ancestry is from Endlfeld, Germany... VERY small town!
https://goo.gl/maps/7JvYW7gPM2RcEjNf7

Kriss KA1GJU