I want to test filters and once again Santa stiffed me on all the fancy test gear I wanted.? It could be my fault as my chimney leads to the boiler.? Anyway, I have an rtl-sdr and an upconverter so all I needed was some clean noise.? Searching lead me to N5ESE's description of using a zener diode.? He references an earlier design by N0SS.? N0SS is now SK and his website is no longer but thanks to archive.org I found this
I breadboarded N0SS's circuit
and lo and behold it works great.? Below shows without and with the noise circuit.? The upconverter adds an offset of +125MHZ
if you are a Spielberg fan and live on a Native American burial ground you should probably skip this.
Doug
AC9RZ
