The WiFi-Texas calculator is the first to calculate total power including the effects of voltage drop.

Our Calculator will give a warning if the link is too long At long distances, the result is unstable and cannot be solved we will suggest minimum voltages for the length entered

If you have more than one device per endpointchange the value in line F

Chinese CCA cat-5 uses 28 awg on the power pairs @ 101 ohms

one CAT-5e spec

Ohms per 100 ft at different temperatures