I had several RF heads – based on AD8317 (and working from PC), also based on AD8313 (you can get entire RF head assembled for ~20$ or so at https://www.sv1afn.com/projects.html) and decided that i need portable box for measuring signal levels and VTX power.
Did that, working well:
it’s actually very simple and entire box costs ~35$ or so (if you have basic parts and attenuators already). Accuracy is acceptable (+/- 1.5dBm in -10 … -40dBm range).
And no, it won’t work better than other tools (even RF explorer is much better with it’s -105dB+ range); it won’t do correct math for frequency (MCU is too weak to do proper calculations). So, if you need serious tool – go look for other solutions. If you need something cheap and working well enough to test antennas/TX/RX – it works good enough.