Electronics > RF, Microwave, Ham Radio

Connect rtl-sdr to 1V p-p sine wave source

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freebil:
Hello. Is it possible to connect to rtl-sdr voltage signals? I read in another thread that it is possible with attenuator? Thanks.

whalphen:
Yes, you can feed your signal through an attenuator to reduce it to the level that's safe for the SDR.  The amount of attenuation depends on the maximum level specified for the SDR.  You can use the formula, dB = 20 log(Vin / Vout), to calculate the needed attenuation.  Alternatively you can feed the signal into a resistor and then place the SDR antenna in the vicinity of the resistor to pick up the radiated signal.  This approach is less consistent or repeatable, but I use it frequently to look at spectral shapes.

freebil:
Thank you very much for the answer, but I cant find the maximum level for the sdr. I have this sdr
http://www.rtl-sdr.com/new-products-rtl-sdr-with-1ppm-tcxo-sma-f-connector-r820t2-bias-tee-improved-tolerances-direct-sampling-break-out-pads-now-available-in-our-store/ .
I will send an email to manufacter of this but what to ask? What is the maximum level of voltage that this sdr can handle as input?

jpanhalt:
I simply made a small loop of solid copper wire and terminated it with 50 ohm.   Connected that to my frequency generator.   Thar was more than enough signal to calibrate my RTL-SDR.

I then tuned up a few known stations of high accuracy (NIST stations).

Such free-air testing is frowned upon, but given the very low signal level and the short time I used it, I figured it was OK.

John

Ammar:
I fed about 100mW of RF power into and rtl-sdr without an attenuator thinking it would damage the device. It got a little warm, but worked fine,

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