[TowerTalk] Using Stubs to Reject Harmonics

[Paul Christensen]

> "Hi Paul, I think you are confusing impedance and resistance here. There is an infinite number of resistance and reactance combinations that will equal 50 ohms impedance but the only ones with low vswr are the ones at or near 50 +j0."

No confusion.  To achieve that 50 +j0 result at the source end of a 1/8-wave line still requires a 50 +j0 termination.  However, no matter what is happening on the load end of the line and as long as it's resistive only, results in a constant impedance of 50-ohms at the source end with a low resistance component and wildly varying amounts of reactance between shorted and open extremes.  But if (and a big "if") a transmitter's output network could efficiently couple into that complex Z seen at the source end of the 1/8-wave line, the result is a dummy load with super-high return loss. 

Paul, W9AC