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Old 13-Sep-2020, 4:33 PM   #50
tripelo
Senior Member
 
Join Date: Jan 2010
Location: Dallas, TX
Posts: 170
Quote:
Originally Posted by rabbit73 View Post
There appears to be spurs in all three of my scanners, but it's not unexpected in equipment that isn't lab grade. ...
Yes.

Quote:
The RTL-SDR dongle has a lot of spurs ...
Have noticed that in the low cost RTL devices. Most of the time not a problem if one is aware of their presence.


Quote:
...I think the Spectrum Spy scanner for the R2 is a lot cleaner than the RSP Spectrum Analyzer for the RSP1A...
Interesting.

Quote:
..The dB scales on my three SDRs are relative, not absolute.
Yes, the unit of dB itself is relative.

When uses as dBm or dB(other), then it takes on more absolute meaning.

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Curious about scale accuracy, sorta related to scale linearity:

Is a dB indicated, an actual dB.

For example:

Is a -20dB indication really 10dB less than a -10dB indication? Or,

Is the delta, 9 or 11 dB or some other number.

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Quote:
...I think there are offset adjustments for the relative scale,...

....I don't think the relative scales of either one could be considered "accurate" with so many stages in series.
Thanks for the information and the images, helps to better understand these interesting devices.

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