Re: A comment about Receiving

Posted by r_zerr on Mar 29, 2011; 4:49am
URL: http://elecraft.85.s1.nabble.com/A-comment-about-Receiving-tp6216105p6217679.html

The antenna tuner acts as a pre-selector so to speak, by making the sytem of the antenna, the transmission line, and the radio, resonant, and matched impedence.

All of this adds up to minimize losses in a couple of ways. The impedence matching means that the xmission line and antenna are as  close to the input impedence of the radio (nominally 50 Ohms these days). If it is not at 50 Ohms then you do not get maximum power in to the rig based on simple simple Ohms law power.

A highly simplified way of explaining resonance part of "a resonant antenna"  is the act of making sure all of the current is in phase with the voltage so that when the power does get to the reciever, that it is in a useable form to drive things. It is somewhat the reverse or inverse of a good spring and shock absorber system on a car....if you have things wrong, and drive along a rough road with bumps spaced jsut right relative to how fast, then all heck breaks loose; maximim power transferred, and that is a resonant system. If things are not resonant, well, you get a smooth ride in your car, or in the case of your radio, poor reception (and transmission).  

-ron WT5RZ