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Roy Lewallen · May 21st 10, 09:55 AM posted to rec.radio.amateur.antenna

wrote:
. . .
Not to mention some of his peculiar theories and notions.
IE: if the pattern of an antenna displays an isotropic
pattern, how in the heck are you going to have large
amounts of gain? The gain would be near zero if using
isotropic antenna as the reference.
Not 32 dbi or whatever number he came up with.
In order to have gain in any direction, a null must form
in some other direction. No free lunch. Sorry. . .

Yep.

As I point out when I give a talk about antenna basics, the isotropic
radiator has the lowest possible gain for any lossless antenna, if you
consider an antenna's "gain" to be its gain in its best direction. In
other words, any lossless antenna has more than 0 dBi gain in some
direction.

I make sure I point this out before I introduce very short and
theoretically lossless dipoles. A free space dipole has a gain in its
best direction of about 2.15 dBi. No lossless antenna can have a gain in
its best direction of less than 0 dBi. So what should we expect the gain
of a very short dipole to be if we could make one with no (resistive) loss?

Roy Lewallen, W7EL