In a pinch I have used simple "T" to split/parallel up to
three SW or scanners. While it did work, the LOs from
one radio would show up in the other receivers.
With VHF/UFH scanners this was a show stopper.

With HF raceivers that up convert "T" work better then
many of us would think. But I still prefer to use a tranformer
based spliter/power divider.

Terry