View Single Post
  #7   Report Post  
Old February 14th 07, 06:04 PM posted to rec.radio.amateur.antenna
art art is offline
external usenet poster
 
First recorded activity by RadioBanter: Sep 2006
Posts: 1,188
Default Antenna Axial Ratio RHCP LHCP

On 14 Feb, 07:52, "art" wrote:
On 14 Feb, 07:18, "Jerry Martes" wrote:





"art" wrote in message


oups.com...


On 13 Feb, 22:18, "Jerry Martes" wrote:
"Bobby" wrote in message


roups.com...


All,


How do you determine the axial ratio from a RHCP wave to a LHCP wave
from an antenna? In essence, I need an axial ratio transformation from
RHCP to LHCP.


Any ideas on the equation or where I can find it will be helpful.


Thanks.


Bobby.


Hi Bobby


If you are working with an antenna that radiates RHCP it is totally
insensitive to LHCP.
If you have an antenna that radiates "RHCP" (or LHCP) the axial ratio
is
the ratio of the Minor axis to the Major axis of the E field. So, it
varies from zero to one as the radiated field varies from Linear to
Circular.


Jerry


You mentioned insensetivity above, are there any other polarities
insensitive to others ? I note that weather antennas are now migrating
to
dual diversity antennas for horizontal and vertical, is it possible to
totally isolate those too.?
Art


Hi Art


I may make mistakes by using non scientific terms. When I read my post,
I realize that nothing is actually defined by my above statement. I would
submit that a LHCP antenna will receive no RHCP signal. I'm sure you know
that any linearly polarized antenna is insensitive to linearly polarized
signals that are orthogonal to the line of polarity of that antenna.
Tell me more about the "weather antennas". What frequency do they use?
Where do they transmit from?


Jerry- Hide quoted text -


- Show quoted text -


Weather experts have found that using both horizontal and vertical
polarizations coming from the same antenna tho in separate pulses that
with oncomming clouds and weather systems that the received picture is
more defined where size of droplets can be determined as well as other
things.
I would suggest that things like wind shear would also be more
discernable.
My antennas because elements are non defined in placement to each
other are capable of multi polarizations which is why I posed the
question.
Art- Hide quoted text -

- Show quoted text -


If you put that same question to Google it would be more informative.
Apparently every forward thinking nations have scientists dabbling
with it
funded by the concern with global warming. I find this all very
interesting because as a ham I had been concentrating on vertical and
horizontal polarizations only Seems like space has opened up the
antenna field such that many will be able to review the path that
antennas have taken over the last century that have appeared to stymy
progress and with an open mind
change course
Art