Fundamentals 1 (mostly about coax)

 I am always thinking about how I can better explain antennas. One thing I have always suggested and try to always do my self is go back to the basics. Until you have a good grasp of the fundamentals it’s hard to progress. That applies to probably everything. Two major things  come immediately to my mind. Softball and antennas! I can’t stress enough how important the fundamentals are in softball and in antennas.


Most of us use coax. Most coax is called 50 ohm coax. The reason is simple. If you terminate any length of coax with a 50 ohm resistor, all the power that reaches the end of the coax will end up in the resistor and turn to heat in the resistor. I say all the power that reaches the end of the coax because there will be some power lost in any transmission line. That’s inevitable. The amount of power lost when the coax is matched to a 50 ohm pure resistive load is usually small. However the load needs to be either 50 ohms with minimal reactance or it needs to be somehow transformed to present a 50 ohm pure resistive load to the coax. This is very fundamental and needs to be remembered.


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