Ed,
You're right, I am 'confusing' omnidirectional with
'omniazimuthal'(?). But, I think if you consider the common
use (or misuse), what I said does hold together. One
example of a vertical array as I was trying to describe is
the 'Ringo Ranger'(2 el.), which is quoted as being
'omnidirectional',
and does have gain over a single element antenna.
As for signals directly overhead, I've never had much
need in receiving them (don't 'do' much VHF/UHF where it may
be desired). And since it's obvious that you knew what I was
referring to, I'm assuming your post is intended to correct my
mis-description. For that I thank you...
'Doc

"'Doc" wrote in message ...
Ed,
You're right, I am 'confusing' omnidirectional with
'omniazimuthal'(?). But, I think if you consider the common
use (or misuse), what I said does hold together. One
example of a vertical array as I was trying to describe is
the 'Ringo Ranger'(2 el.), which is quoted as being
'omnidirectional',
and does have gain over a single element antenna.
As for signals directly overhead, I've never had much
need in receiving them (don't 'do' much VHF/UHF where it may
be desired). And since it's obvious that you knew what I was
referring to, I'm assuming your post is intended to correct my
mis-description. For that I thank you...
'Doc


Doc & Richard:


I wasn't trying to correct anybody, but I was being a bit pedantic in
defining "omnidirectional." People often approach the subject of antenna
patterns with a set of "assumed conventions", based on their area of
interest. TV broadcasters are near universally trying to target receivers
that are essentially at ground level. Any power directed more than just a
bit above horizontal is wasted power! But if you design GPS antennas, you do
a lot of thinking about the pattern at higher elevations.

If we stick to a rigorous interpretation of a three-dimensional co-ordinate
system, we can talk about any kind of antennas for any kind of service.

Ed
wb6wsn

Ed wb6wsn wrote:

Doc & Richard: I wasn't trying to correct anybody ...
________________

Me either, just pointing out that antenna patterns can be omnidirectional in
one plane, and not in another. By this reality the original poster's phrase
"omnidirectional beam" may not be a conflict of terms.

In the case of most FM/TV broadcast antennas, the net pattern basically is
omni in the horizontal plane, and a narrow beam in the vertical plane. This
can increase their peak h-plane gain well above that of a simple dipole --
to produce an "omni antenna with gain," by FCC definition.

RF

"Richard Fry" wrote:
Elevation pattern nulls do occur in these antennas, though.
______________

I should add that it is possible, and a common practice in specifying TV &
FM broadcast transmitting antennas to "fill" these nulls in their elevation
patterns (i.e., to prevent them from dropping to a theoretical zero ERP).

RF