Topband: Return Loss Question?

Jim Brown jim at audiosystemsgroup.com
Fri Jan 15 15:45:05 EST 2021


On 1/15/2021 12:09 PM, Tree wrote:
> Anything over 20 db is pretty good.  15 db is acceptable - 10 db is a
> little too much like for a transmit antenna.  You can convert it to SWR if
> that makes it make more sense.

I have a different view of this issue, relating it to 1) will the 
rig/power amp deliver full power to the line and 2) how much excess loss 
is there due to the mismatch. My vintage Ten Tec Titans were happy 
driving a 3:1 mismatch, and the excess loss on the 220 ft runs to my 160 
antennas with 2:1 VSWR is less than 0.1 dB, much less on the 40 ft run 
to my Tee vertical.

My 87A is far less forgiving about VSWR, starting to get unhappy with 
more than about 1.8:1. And the tuner in my KPA1500 happily drives 3:1 or 
higher VSWR.

I am more concerned with VSWR on the higher bands, especially 6M, where 
most of my feedlines are 300+ ft of 7/8 hardline.

73, Jim K9YC


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