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Old November 20th 03, 01:24 AM
Dave Shrader
 
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nathan wrote:

I have always heard that this is true, and that I should tune antennas
for maximum field strength and not for minimum SWR. Why wouldn't they
occur at the same time?

Nathan


Maximum field strength, far field strength, occurs when the antenna is
radiating the MAXIMUM power delivered to it. [Irms^2*Rradiation]

Minimum VSWR occurs when the load impedance of the antenna matches the
characteristic impedance [Zo] of the transmission line.

At my previous location I had a very efficient antenna, 1/2 wavelength,
fed with 600 ohm transmission line with a VSWR of more than 20:1.

The difference is between the radiation resistance [Rradiation] of the
antenna and the feedpoint impedance of the antenna. They are NOT the
same thing!

Deacon Dave, W1MCE