Richard Fry wrote:
"Cecil Moore wrote
Richard Fry wrote:
Cecil, hopefully you understand that even isotropic radiators near each
other and excited on the same frequency with the same amount of power
will generate far-field pattern nulls.

Maybe I'm misunderstanding you.

I'm trying to understand how a line drawn between two
"isotropic radiators near each other" could ever be
in the far field.

Everywhere it exceeds 2*D^2/lambda in length, where D is the greatest
dimension of the array.

Are you saying that the sources that are "near each other"
are far enough apart to be in each other's far field?
How could that be if the two sources are D apart?
--
73, Cecil http://www.w5dxp.com

"Cecil Moore"
Everywhere it exceeds 2*D^2/lambda in length, where D is the greatest
dimension of the array.

Are you saying that the sources that are "near each other"
are far enough apart to be in each other's far field?
How could that be if the two sources are D apart?
_________

It isn't necessary for the radiators to be in each other's far field.

Here is a link to a plot of the far-field elevation pattern of a linear
array of three isotropic sources at one lambda vertical spacing.

http://i62.photobucket.com/albums/h8...picSources.gif

RF

Richard Fry wrote:
It isn't necessary for the radiators to be in each other's far field.

I'm just trying to understand your point. You said there
are nulls in the far field. If the radiators are not in
each other's far fields, how could the line drawn between
them be in the far field?
--
73, Cecil http://www.w5dxp.com

"Cecil Moore" wrote
I'm just trying to understand your point. You said there
are nulls in the far field. If the radiators are not in
each other's far fields, how could the line drawn between
them be in the far field?


X Iso source 1

=================== to far field, where nulls will exist

X Iso source 2,
1 lambda from
Iso source 1



RF

Richard Fry wrote:
"Cecil Moore" wrote
I'm just trying to understand your point. You said there
are nulls in the far field. If the radiators are not in
each other's far fields, how could the line drawn between
them be in the far field?


X Iso source 1

=================== to far field, where nulls will exist

X Iso source 2,
1 lambda from
Iso source 1

No, no, no, Richard. The line is drawn from one source to
the other source. Your line is not drawn from either
source to the other source.
--
73, Cecil http://www.w5dxp.com

"Cecil Moore" wrote
No, no, no, Richard. The line is drawn from one source to
the other source. Your line is not drawn from either
source to the other source.
__________

Obviously we are not talking about the same net radiations patterns.

Carry on.

RF

Richard Fry wrote:
"Cecil Moore" wrote
No, no, no, Richard. The line is drawn from one source to
the other source. Your line is not drawn from either
source to the other source.

Obviously we are not talking about the same net radiations patterns.

Sorry about that. English semantics strikes again. Your
line was indeed "between" the two sources but not the
"from - to" line that I had in mind when I said "between". :-)
--
73, Cecil http://www.w5dxp.com