Hello, I am in the security industry and am tried of paying big $$$ for video baluns. (75 ohm cctv / coax to 100 ohm video on cat5) I have opened one up and it appears to be an impedance matching transformer however.... there are no part numbers on it. Could anyone be so kind as to help me out with a spec for the balun so I can pick one up at the local electronics shop... Forever in your debt...