Re: [Discuss-gnuradio] wrong dB

[Marcus Müller]

There's no calibration in such SDR devices. The dB values you see in a
GUI are "dB relative to full scale" (and "full scale" is typically 1.0),
often with some normalization due to how the DFT was calculated. These
values are (idealizing) *proportional* to the power in dBm, but they are
*not* the same. The proportionality factor is result of the signal
processing chain and will be different for different programs.

Please don't use Nabble. It breaks discussions!!! It is a **bad**
frontend to the mailing list. Sign up directly with your email address
on https://lists.gnu.org/mailman/listinfo/discuss-gnuradio , please. I
will not react to further messages sent through Nabble.

Best regards,
Marcus


On 20.06.2017 16:10, GNUBeginner wrote:
> Dear Marcus,
>
> If I may, I would like to ask for your guidance please. I have been
> experimenting with gr-scan via command line and QSpectrumAnalyzer GUI.  
>
> After injecting -15 dBm signal with 20 dB attenuator at 2412 MHz WiFi
> channel to the HackRF One, somehow I am seeing -53 dB peak power with
> gr-scan and -51 dB peak power with QSpectrumAnalyzer GUI.  
>
> I am not sure what these values are. This has to be a calibration issue.
> Could you please help me understand what these values are?  
>
> Thanks
>
>
>
>
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