Hello Gerhard,
1) We have two graphical ways to control the TG, either through the Spike software and through the application TGStandalone.exe found in the Spike installation directory at C:/Program Files/SignalHound/Spike/. Both ways only allow you to set the amplitude and frequency manually.
2) The output level on the TG is between -10 and -30.
Outside of the scalar mode, the TG is a simple CW generator. Yes, the scalar mode is primarily built around return loss and insertion loss measurements, filters and antennas being two of the larger use cases.
If you want to talk in more depth about your measurement requirements offline, you can email us at support at signalhound dot com.
Regards,
Andrew