Indeed SWR is not a measure of Yagi antenna performance.
However Yagi performance IS a function of the narrow bandwidth of a shortened
PARASITIC element. (not the driver)
Explained here regarding a 2el short 40m Yagi:
https://youtu.be/VZ9esNGBP7Y?si=Xj8shPN9NnNALw8O
<https://youtu.be/VZ9esNGBP7Y?si=Xj8shPN9NnNALw8O>
Steve, ve6wz
> Yes, but extensive modeling shows that SWR bandwidth is the only important
> downside of loading that is not inductors at the feedpoint.
>
> SWR is NOT a measure of antenna performance, and the added loss due to SWR
> values below 3:1 at the feedpoint are too small to matter unless you're using
> line smaller than RG8/11, and/or the lines are very long. My 80M dipole at
> 125 ft fed with about 170 ft of a good RG11 presents a 5:1 SWR on 60M at the
> TX, but is quite effective running legal limit (100W ERP).
>
> 73, Jim K9YC
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