A bit about Splitters

There are two characteristics of RF Splitters.  The frequency range they are work with, and the signal loss that happens when a signal passes through them from input to output.

The VHF, UHF, FM, and CATV bands operate in a frequency range of 55 Mhz to 900 Mhz.

The signal loss, called insertion loss, is measured in dB. You want to have the lowest dB possible to have the least loss.  A good splitter provides the same amount of loss for all outputs.  That means it is "equally balanced."  This is true of most splitters with two, four, or eight outputs. But many splitters with three outputs are unbalanced because one output will have less loss than the other two!  You want to get a splitter that provides close to 4.0 dB per split. An average quality splitter has around 4.5 dB loss per split. (A two way splitter has one split, a four-way has 2 splits, and an eight way has 3 splits.) So, your basic eight-way splitter would have about 12 to 13.5 dB loss.

Splitters also may or may not pass DC current through, from input to output.  Normally a splitter will block DC, but a manufacturer can add circuitry to allow DC pass.  (They are basically multi-tap transformers.) A DC passing splitter is required when DC must travel up the cable to supply coax-powered equipment.  Examples would be an in-line amplifier, or a remote video camera.  DC passing splitters cost more, but they generally also have less loss.

An average splitter has a few ferrite cores with wires wrapped through them hand soldered to the terminals. This can be inconsistent, causing variations in the insertion loss for the various outputs, and maybe different losses will occur at different frequencies.  That's undesirable.

The better splitters will not have these problems, and will always work the same, unit to unit.

And FYI, if you hook up any splitter backwards, it will work as a combiner.