Correct!
In the example I gave, had the 10:1 SWR been caused by a 5 Ohm load
rather than a 500 Ohm load, the current would have been a maximum at the
load (3.16A) and the loss/unit length at that point would have been even
higher than the simple loss calculators predict - the reverse of the
high impedance case.
Only when the line is long enough to encompass a large proportion of one
cycle of the SWR pattern does it begin to "average out".
For loss calculations on electrically short lengths of mismatched line,
you can't rely on any calculator that takes only SWR as input.
Steve G3TXQ
On 09/11/2013 22:37, Joel Hallas wrote:
The conclusion is that the popular graph of "additional loss due to
mismatch" in "The ARRL Antenna Book" for many years is really "average
additional loss due to mismatch for cables much longer than a wavelength"
over which both high and low current conditions will exist.
Regards, Joel Hallas, W1ZR
Westport, CT
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