>
> Any dipole mounted somewhere above a good ground, could have some gain in
> some directions ... compared to a dipole in free space ... and so it would
>
exhibit a positive dBd number. And many do. There is no snake oil in that.
Really?
Do you know of a product that would allow me to mount my comparison dipole
in free space for tests?
To use dBd to refer specifically to a dipole in free space is misleading
marketing BS.
If antenna makers were interested in clear reporting of their products
specifications, dBi would be the only gain number specified with respect to
an ideal theoretical source. I know that it is not always used this way,
but when dBd gain is published, it should express the gain over a dipole
mounted at the same height over the same earth conditions.
It's no fair trying to claim that dBd means "gain over a dipole in free
space" The clear, misdirection free use of dBd is "gain over a dipole in
the same location." That has meaning and is a useful gain measurement,
because it automatically subtracts out any ground gain advantage.
A dipole has zero dBd gain no matter where you install it. I know some
disagree with that, but it doesn't make one bit of sense to use it at ALL
otherwise.
You want to refer to the gain including ground gain of some installation,
use dBi.
73
Dan
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|