Even advanced (3rd year degree level) textbooks, such as Ramo, Whinnery and
Van Duzer's
"Fields and Waves in Communications Electronics" (Which was a 3rd-year
textbook me in 1972)
discuss the wavefron as it might appear some distance away from antennae in
the (very) far field.

What, though, is the shape of the emitted wave close-in to antennae? For
example, at opposite
ends of a half-wave dipole, the electric filds are equal and opposite, so
cannot be producing the
same part of the expanding wave.

Might such an analysis reveal the reason why short antennae are poor
radiatiors of RF?

"gareth" wrote:
Even advanced (3rd year degree level) textbooks, such as Ramo, Whinnery and
Van Duzer's
"Fields and Waves in Communications Electronics" (Which was a 3rd-year
textbook me in 1972)
discuss the wavefron as it might appear some distance away from antennae in
the (very) far field.

What, though, is the shape of the emitted wave close-in to antennae? For
example, at opposite
ends of a half-wave dipole, the electric filds are equal and opposite, so
cannot be producing the
same part of the expanding wave.

Might such an analysis reveal the reason why short antennae are poor
radiatiors of RF?

Twaet.

--
STC // M0TEY // twitter.com/ukradioamateur

On 9/16/2015 9:42 AM, Stephen Thomas Cole wrote:
"gareth" wrote:
Even advanced (3rd year degree level) textbooks, such as Ramo, Whinnery and
Van Duzer's
"Fields and Waves in Communications Electronics" (Which was a 3rd-year
textbook me in 1972)
discuss the wavefron as it might appear some distance away from antennae in
the (very) far field.

What, though, is the shape of the emitted wave close-in to antennae? For
example, at opposite
ends of a half-wave dipole, the electric filds are equal and opposite, so
cannot be producing the
same part of the expanding wave.

Might such an analysis reveal the reason why short antennae are poor
radiatiors of RF?

Twaet.

It is better to light a single candle than to curse the darkness.

--

Rick

On 9/16/2015 11:47 AM, rickman wrote:
On 9/16/2015 9:42 AM, Stephen Thomas Cole wrote:
"gareth" wrote:
Even advanced (3rd year degree level) textbooks, such as Ramo,
Whinnery and
Van Duzer's
"Fields and Waves in Communications Electronics" (Which was a 3rd-year
textbook me in 1972)
discuss the wavefron as it might appear some distance away from
antennae in
the (very) far field.

What, though, is the shape of the emitted wave close-in to antennae? For
example, at opposite
ends of a half-wave dipole, the electric filds are equal and
opposite, so
cannot be producing the
same part of the expanding wave.

Might such an analysis reveal the reason why short antennae are poor
radiatiors of RF?

Twaet.

It is better to light a single candle than to curse the darkness.


But remember, you cannot win an argument with an ignorant person.