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Originally Posted by tripelo
When you have the scanners them properly adjusted, have you seen any spurs in either scanner?
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There appears to be spurs in all three of my scanners, but it's not unexpected in equipment that isn't lab grade. I would need a pure source to really tell the spurs from actual signals.
The RTL-SDR dongle has a lot of spurs when I put a 75 ohm termination resistor on the front end, but they are minimized when signals are measured.
I think the Spectrum Spy scanner for the R2 is a lot cleaner than the RSP Spectrum Analyzer for the RSP1A.
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Your images and videos are informative.
Good to see a comparison of both scanners displays.
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Thank you. I was curious to make the comparison myself.
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Reading the scale looks like about 60+ dB dynamic range displaying those particular signals.
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A 12 bit ADC should be able to do at least a 60 dB dynamic range.
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Have you checked the accuracy of the dB scale?
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The dB scales on my three SDRs are relative, not absolute. There is one exception, the calibration of the RSP1A with the SDRuno software is calibrated under certain conditions:
SDRplay RSP2 for accurate RF power Measurement
https://www.youtube.com/watch?v=MRR-x_TjOp4
This is my test of the SDRplay calibration:
I have used that feature to measure the strength of TV signals, but a correction factor of about +14 dB is needed:
Measuring TV Signal Strength with an SDR
https://www.avsforum.com/threads/the.../post-59870798
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Is there a means in software to calibrate the dB scale against a reference?
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I think there are offset adjustments for the relative scale, but I haven't hunted for them because the position of the signal changes with adjustments of gain and display.
I think the calibration feature of the SDRuno mentioned above is fixed in the hardware or firmware.
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Wonder, when calibrated at one or two points, if it maintains some accuracy over a larger range of dB?
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I have not tested the linearity of the relative dB scales. The accuracy of the "use under certain conditions" calibration of the SDRuno with RSP1A SDR appears to hold well over a wide range.
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Do you think one of the two scanners could be more accurate than the other?
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I don't think the relative scales of either one could be considered "accurate" with so many stages in series.