The tinySA is an amazing product for the price and can be used just like an expensive Spectrum Analyzer when combined with an attenuator and some basic knowledge. This video shows how to combine a home made attenuator and a tinySA Ultra to check a real transmitter for FCC compliance as well as verifying it's putting out it's advertised power.
If you are new to RF and working with radios, this video provides some great starting points for you and shows you some of the in and outs of the tinySA as well as the NanoVNA.
tinySA Ultra:
https://amzn.to/3ZQH9MZ
NanoVNA
https://amzn.to/4gUrDWj