Re: Only noise when connected to the antenna #v6


Jonathan Kayne, KM4CFT
 

I have published a YouTube video that goes through my findings. I was also trying to explain how the circuitry works. I show spectrum analyzer readings as I explain it so it might help.
https://youtu.be/pQb-sM8slCg

Curt, I did indeed check each oscillator and they were all working as expected. In fact that was the first thing I checked when I started troubleshooting. I also observed that the LO would appear at the output of the mixer due to nonlinearities of the mixer. 

Evan, I have tested up to the product detector stage. It is of course possible that one of the transformers isn't working properly, but I will say that I checked the product detector by inserting a 1 kHz -50 dBm (that's the lowest the function generator could do as the Agilent I was using for testing is 100 kHz minimum and had to switch to the lower frequency SG) into the audio side and it mixed the baseband up to 11 MHz. The weird thing about that was that the signal appeared to be amplified and not attenuated (by about +28 dBm if I remember correctly) maybe that signal generator wasn't as accurate as the Agilent...

-Jonathan, KM4CFT

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