The adapters and tuners are listed / edited in a tree

The rows have the following functions

Enabled
If selected, the IPTV service will be enabled an use for channel subscriptions.
Name
The name of this tuner.
OTA EPG
Allow OTA EPG (epggrab) scan on this input device
Priority
The tuner priority value (higher value = higher priority to use this tuner).

LinuxDVB specific rows

Keep FE open
Enable to not close the LinuxDVB frontend device in the idle state.

SAT>IP specific rows

Full Mux Rx mode supported
Enable, if the SAT>IP box supports the full mux rx mode (pids=all) parameter.
Signal scale (240 or 100)
Some SAT>IP boxes has only 0-100 scale. If your signal is too low, try value 100 here.
Maximum PIDs
Maximum supported PIDs in the filter of the SAT>IP box.
Maximum length of PIDs
Maximum length in characters for the command setting PIDs to the SAT>IP box.
addpids/delpids supported
Enable, if the SAT>IP box supports the addpids/delpids command.
PIDs in setup
Enable, if the SAT>IP box requires pids=0 parameter in the SETUP RTSP command.
Force pilot for DVB-S2
Enable, if the SAT>IP box requiest plts=on parameter in the SETUP RTSP command for DVB-S2 muxes.
UDP RTP Port Number (2 ports)
Force the local UDP Port number here. The number should be even (RTP port). The next odd number (+1) will be used as the RTCP port.
Satellite Positions
Select the number of satellite positions supported by the SAT>IP hardware and your coaxial cable wiring.
Master Tuner
Select the master tuner.

The signal from the standard universal LNB can be split using a simple coaxial splitter (no multiswitch) to several outputs. In this case, the position, the polarization and low-high band settings must be equal.

If you set other tuner as master, then this tuner will act like a slave one and tvheadend will assure that this tuner will not use incompatible parameters (position, polarization, lo-hi).

Next tune delay in ms (0-2000)
The delay before tuning in milliseconds after tuner stop. If the time after previous start and next start is greater than this value - the delay is not applied.
Send full PLAY cmd
Send the full RTSP PLAY command after full RTSP SETUP command. Some device firmwares requires this to get MPEG-TS stream.
Force teardown delay
Force the delay between RTSP TEARDOWN and RTSP SETUP command (value from 'Next tune delay in ms' is used). Some devices are not able to handle quick continuous tuning.