DIY Spectrum Analyzer 0 to 1750MHz (1999)

Re:DIY Spectrum Analyzer 0 to 1750MHz (1999) by jjoonathan on Wednesday January 02, 2019 @11:03AM (#18807041)

SDRs are total spur-fests, yes, but at 0% the cost of a real SA (rounded) the economics sometimes work out :-)

That said, at the high end of the SDR range, the new AD937x chips ($325 in qty 1k!) make impressive claims wrt automagic spur suppression. They still don't beat high-IF or YIG preselected SAs, but now they claim to be in the ballpark under non-overload conditions. Has anyone here dug deep enough to comment?

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Re:DIY Spectrum Analyzer 0 to 1750MHz (1999) by madengr on Wednesday January 02, 2019 @12:03PM (#18807698)

The pre-selection is a big deal. The AD936x needs good front end filtering to reject n*LO. For instance 5x146 MHz = 730 MHz, which translates that 730 MHz nation-wide LTE signal smack-dab into the 2m amateur band. Unless they have a new front-end architecture in the AD937x, all the I/Q calibration won't help them.

Of course as you said, for $325 it's not a consumer chip, so some $ will be spent on external passives.

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Re:DIY Spectrum Analyzer 0 to 1750MHz (1999) by jjoonathan on Wednesday January 02, 2019 @03:02PM (#18809601)

Ah, right, I/Q calibration can't suppress anything out-of-band. Makes sense.

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