I'm reading an article about antenna aperature. Is it correct to state
that dipoles have a very large aperature and something like a horn
assembly used in microwaves has a tiny aperature except for wavelength
for which the horn is designed?

Just trying to get a handle on this advanced theory.

"Michael R. Davis" wrote in message
...
I'm reading an article about antenna aperature. Is it correct to state
that dipoles have a very large aperature and something like a horn
assembly used in microwaves has a tiny aperature except for wavelength for
which the horn is designed?

Just trying to get a handle on this advanced theory.

Dipole aperture is the capture area which translates an incident field, in
W/m^2, to the actual power received by the dipole. For example the aperture
for a half wave dipole is 0.13(Lambda)^2, where Lambda is the wavelength in
meters. A 40 m half wave dipole would therefore have an aperture of 52
m^2. A horn aperture, and also a parabolic dish, aperture is the physical
area of the mouth of the horn.

Regards.

Frank

Frank wrote:


Dipole aperture is the capture area which translates an incident field, in
W/m^2, to the actual power received by the dipole. For example the aperture
for a half wave dipole is 0.13(Lambda)^2, where Lambda is the wavelength in
meters. A 40 m half wave dipole would therefore have an aperture of 52
m^2. A horn aperture, and also a parabolic dish, aperture is the physical
area of the mouth of the horn.

Regards.

Frank


Well, I sure read _that_ wrong! Thanks for clearing that up.

It's not advanced at all. If both antennas are equally efficient, the
ratio of their apertures (in square wavelengths) is exactly equal to the
gain of one relative to the other.

Roy Lewallen, W7EL

Michael R. Davis wrote:
I'm reading an article about antenna aperature. Is it correct to state
that dipoles have a very large aperature and something like a horn
assembly used in microwaves has a tiny aperature except for wavelength
for which the horn is designed?

Just trying to get a handle on this advanced theory.

Michael R. Davis wrote:
I'm reading an article about antenna aperature. Is it correct to state
that dipoles have a very large aperature and something like a horn
assembly used in microwaves has a tiny aperature except for wavelength
for which the horn is designed?

Just trying to get a handle on this advanced theory.

Hi Mike:

You didn't state what you were reading specifically but this free
on-line book seems to be well researched and read.

http://www.qsl.net/n1bwt/contents.htm

73,

John - WD1V
FN-42