Foundations Of Amateur Radio

Foundations of Amateur Radio There is a recurring question that never seems to get a straight answer. Why are we using 50 Ohm impedance and not 75 Ohm? The more people you ask, the more answers you get. There'll be commentary about standing waves, SWR, loss, incompatibility, soldering, cost, velocity factor, diameter, susceptibility to noise and the list goes on and grows, the more people you ask, the longer the list. Of course as time goes by, people remember stories told to them, guess, or even, how to say this, make stuff up. To steal a phrase: "Why is it so?" In the 1930's, when most of us were not even the apple in the eye of their parents - let alone their grand parents - coaxial cable was being developed for kilowatt radio transmitters. There are two aspects to consider, the amount of loss against length and the ability of the coax to handle power. Without going into the maths, there's plenty of that online, the lowest loss for air-dielectric cable is 77 Ohms. If we look at the peak power handlin