Michael Tope wrote:
> If on the other hand, I just tell you that the antenna
> has +3dBi gain in the direction of the incoming plane
> wave and that the incoming plane wave has a power
> density of 10 microwatts/meter^2, you won't be able
> to tell me the level of the received signal (not enough
> information).
If the wavelength is known, as it normally is,
then effective area can be calculated from isotropic gain,
and vice versa:
Ae = Gi * lambda ^ 2 / (4 * Pi)
Gi = 4 * Pi * Ae / (lambda ^ 2)
The origin of this topic came from a false assumption
that the "capture area" of a very long wire antenna
is large simply because of the length of the wire,
and regardless of the directivity.
This was shown to be entirely wrong: effective area
and gain are proportional to each other.
In directions of low gain the effective area is small
regardless of the length of the wire, or countries worked :-)
73,
Sinisa YT1NT, VA3TTN
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