LT5517 SDR receiver

[ealex]

Hello

I've been playing with a LT5517 based receiver: LT5517 datasheet

The schematic is simple, using the datasheet and and example from "GR1-MANUAL 1021 KTH-SDR WIDEBAND RECEIVER"

It works quite well - very sensitive even with a bad antenna ( 3 loops of wire taped on the inside of a window ) ,  but i's fussy about the LO input signal - a si570 based LO is useless - square wave output

For now i use a signal generator and ~ -5 dBm for LO over 40 MHz ( a pll based VCO is planned, but next year ). For LO under 40 MHz i need to go to 0 dBm .

Also, because of it's huge bandwidth - 40 to 900Mhz it needs very good input filters, otherwise it gets overloaded ( need to build them also )

I've attached a picture of the board, the schematics in KiCad and some sample audio files - the final.mp3 one got some air traffic data, processed to remove the silent portions and heavily compressed.
The other one is a weak JT65 signal - i think it can be decoded from this file