PE1NJN, Bart, did do me a big favour by re-drawing the circuit diagram. He also designed PCB layouts for the “Speccie” mainboard, the power supply and a “Tunerboard” which is designed for the FI1216 tuner.
Do not expect to end up with a “High End” Spectrum Analyzer, this design will give you a lot of satisfaction but the quality depends on what you use for the RSSI part of the diagram.
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Please note that the pdf files have their information in the left bottom corner. At first, when opening, it could look like an empty pdf file, but it’s not.