On Sat, Nov 26, 2022 at 05:45 PM, John Cunliffe W7ZQ wrote:
Not really, if you use the low level output and amplify it with low noise MMIC you have recovered your signal and have plenty of reverse isolation to have full dynamic range.If you set the LO output on, you have to use either an isolator or other means to prevent signal leaking back into the lo output. Signal leakage back into the LO port is the main reason for low dynamic range.? I found using the isolation generated by the internal switch to be a lot better and the signal flatter than try and isolate it using other means when I designed the tracking generator for the original TinySA . And sure, a NanoVNA is better, but that is not the point of my exercise.
If you are getting 90dB or more isolation with your design, you might want to share the details and see if Erik can produce a tracking generator accessory for the tiny SA/tinySA ultra.
Herb
