Hi all,
I want to share my latest project, a 1.8GHz spectrum analyzer.
Technology (see first picture):
Double/triple conversion with passive mixer modules from eBay and ADF4351/SI5351 modules from ebay as LO's
Log amp (from AD8307 data sheet) for DIY wide RBW and audio based FFT stitching for small RBW
Arduino zero for embedded control and everything else on PC
SW also DIY based on .net so PC only
Specs:
DC (I tested down to 10 Hz) till 1.8GHz
IIP3 +18dBm (see second picture)
Spur free dynamic range (depending on RBW) at least 70dB
RBW from 300kHz to 1Hz (See third picture) Dynamic range reduced (but still acceptable) at small RBW due to phase noise of ADF4351
Phase noise acceptable (see fourth picture)
And results of an actual measurement of harmonics of a signal generator as fifth picture (ignore the IIP3 text at top of display, forgot to switch of)
All still without shielding so you may notice some spurs