Does a (non-splitting) cable splitter degrade the signal?
I believe it is splitting the signal, each output will have a specific loss associated. Some splitters will unevenly split the signal (commonly called a tap), which is handy to give a better signal to a longer run or to the cable modem. You can get a straight through connector at any HI store. That said, even these will have some loss of signal, just no where near as much as from a splitter.



Note: Common Insertion Loss per output leg on passive splitters:


2-way - 3dB
3-way - 4.8dB
4-way - 6dB


3dB is 1/2 the signal strength, basically on a two way splitter, full power goes in, 1/2 comes out each leg as long as there is termination impedance on all (cable or terminator cap) ports.