Topband: 50 ohm direct burial coax cable

Jim Brown jim at audiosystemsgroup.com
Sat Jun 14 01:10:13 EDT 2014


On 6/13/2014 9:51 PM, Tom W8JI wrote:
> The worse case SWR of a 50 ohm system with 75 ohm cable isn't 1.5:1 
> when normalized to 50 ohms. It is 2.25:1. 1.5*1.5 = 2.25 

Wrong. If you're using 75 ohm line, it's a 75 ohm system -- the system 
impedance is the line impedance. It's the the match of the load to the 
line that determines SWR, and the excess loss due to mismatch. So 
"normalizing" to 50 ohms when you're using 75 ohm coax is simply wrong.

73, Jim K9YC


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