If you know the difference in RSSI readings between your client devices and the adapter you are using for passive surveys, then you have two options:
1. Adapter Signal Level Correction – allows you to adjust the signal strength reported by your Wi-Fi adapter. This is done before the surveys and cannot be changed later. Find it at Main Menu -> Settings.
2. Client Capabilities: you can create a custom preset for your client device and apply that to the visualizations and reports. This will also be combined with the Requirements.
This can be done after the survey is complete, besides, you can have several presets and see the results with the eyes of different client devices.
Read more in the Client Capabilities help chapter:
https://www.tamos.com/htmlhelp/tg/configuring_tamograph.htm#Client_Capabilities