[TowerTalk] balanced line loss on a mismatched antenna

Jim Brown jim at audiosystemsgroup.com
Tue Feb 28 09:36:11 PST 2012


On 2/28/2012 8:18 AM, Paul Christensen wrote:
> the Yagi gain is as good or
> better even at lower angles. In addition, the feedpoint impedance has increased to a much more manageable value.

Yes. I've got a 2-el wire Yagi for 40M pointed ENE, and it works really 
well to AF and the east coast of the US. I'm feeding it with 50 ohm 
line, and the SWR is better than 2:1.  I also have a dipole broadside to 
more or less the same direction. Both antennas are up about 110 ft.  The 
dipole is sometimes better to EU.  I'm about 70 miles S of San Francisco.

As Paul has noted, the W8JK is a rather difficult antenna to build and 
feed, and the gain is easily eaten up in losses both in the wires that 
make up the antenna and the feedline. Also, while 50 ohm coax is a 
strong mismatch, it's still much less of a mismatch than 450 ohm line.

73, Jim K9YC




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