[Elecraft] dBd vs dBi

[k6se@juno.com]

Stuart, K5KVH wrote:

"Good comments on SteppIR claims, Earl."
==========
It dawned on me that the SteppIR 3-el Yagi automatically adjusts the
elements for max gain and min SWR when you QSY, therefore bandwidth is
not a concern like it is with other antenna manufacturers, so I don't
want to sell the SteppIR short.

I don't know if their claim of 8.81 dBi gain is for every frequency on
all bands from 14.000 to 29.900 MHz, but I can model 3-el Yagis for
absolute max gain for say, 28.500 MHz, on a 16-foot boom to see if it's
possible to achieve 8.81 dBi with a very narrow bandwidth.

Maybe one of you guys knows the frequencies for which their 8.81 dBi gain
figure is valid for.  If so, please let me know.  Also, what kind of
system do they use for matching to 50-ohm coax (when a Yagi is tuned for
absolute max gain, the feed impedance is very low).

Will report my findings when I get some spare time to try it.

73, de Earl, K6SE