Here is the scenario:
1) Antenna A and Antenna B located above a stage.
2) Antenna A signal is split using the UA221 into A1 and A2.
3) Antenna B signal is split using the UA221 into A1 and B2.
4) Low-loss RG213/U cable bring A1 and B1 to a wall plate at the rear of the room, east side.
5) Low-loss RG213/U cable bring A2 and B2 to a wall plate at the rear of the room, west side.
6) A rack mounted portable wireless system will connect to the east plate, or to the west plate.
When the east plate is being used, is it recommended to terminate the west plate to improve the RF performance or to minimize RF interference?
Our opinion is:
1) Loading the unused A/B RF outputs with 50 ohm BNC terminators certainly could not hurt.
2) However, the termination is probable unnecessary in realistic terms. The un-terminated runs are not likely to insert RF interference back into the UA221.
3) The UA221 splitter, being passive, is a power divider, so each split output is 3 dB less than the un-split feed.
4) Using 50 ohm terminators will physically protect the unused BNC wall plate connectors, and may prevent someone bent on mischief from breaking off a pencil lead in the unused BNC connector. Experience is an effective teacher.