Re: High SWR on all HF Bands


Steve W3AHL
 

Dennis,

The length of coax will affect the SWR seen at the radio.  Using a simple program like Transmission Lines for Windows, supplied with the ARRL Antenna Book, will show how much it varies.  Transmission lines are often used for matching purposes in antenna designs for single band antennas.  A quarter wave (electrical length) transmission line is an impedance inverter and can dramatically change the measured SWR, compared to a half wave line.  

But an unbalanced antenna with no common mode choke at the feed point will also exhibit the same behavior, along with distorted audio or other problems due to high RF in the shack.

Steve, W3AHL

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