Yes, the RF Scan sets the gain to 29.7 at start of scan. A gain of 29.7 is used as it is a median value. Too high (49.6 and AGC) or too low (less than say 15) gain during RF scan will not give results which correctly show the interfering signals.
Unfortunately the scan does not set gain back to original value at the end of the scan.
The Gain optimization scripts also leave the gain set to a low value when these complete their cycle.
In both these tests, the user should manually set gain back to the value it had before start of these tests.
By the way, have you seen this thread about mods to include (display + set) gain from SkyView dump1090-fa map / dump1090-mutability map?
Read / Set Gain from SkyView and Gmap
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