Prev: Suspending the US Constitution
Next: California schools $120M solar project
From: John Larkin on 31 May 2010 13:26
On Mon, 31 May 2010 08:15:14 GMT, tomasferrel(a)lopsler.com (Tomas
Ferrel) wrote:

>"Antennas with orthogonal elements that are combined in phase
>quadrature such as the crossed dipole with external 90 degree hybrid
>coupler. This type of antenna can produce right-hand and left-hand
>circular polarization simultaneously."
>
>"Simultaneously"? Can anyone explain how this works? What is the
>confguration of the coil and how is the signal applied to produce this
>effect?
>
>I don't understand how the "simultaneous" LH and RH fields would not
>cancel each other out. Perhaps they mean the applied signal can cycle
>intermittently between LH and RH.
>
>Tomas Ferrel

I think some systems send two different signals simultaneously using
rh and lh polarization.

John

From: Paul Keinanen on 31 May 2010 17:33
On Mon, 31 May 2010 08:15:14 GMT, tomasferrel(a)lopsler.com (Tomas
Ferrel) wrote:

>"Antennas with orthogonal elements that are combined in phase
>quadrature such as the crossed dipole with external 90 degree hybrid
>coupler. This type of antenna can produce right-hand and left-hand
>circular polarization simultaneously."
>
>"Simultaneously"? Can anyone explain how this works? What is the
>confguration of the coil and how is the signal applied to produce this
>effect?

In a crossed dipole system, you can produce either RHCP or LHCP
signals depending on how the phasing harness is connected.

However, if you bring down both the horizontal as well as the vertical
dipole signal on separate cables to the RF amplifier (and possible to
the IQ down mixer), you can then create both sum and difference
signals to get both RHCP as well as LHCP signals.

IQ and MIMO (Multiple Input, Multiple Output) might be usable keywords
to limit the Google search.


First  |  Prev  | 
Pages: 1 2
Prev: Suspending the US Constitution
Next: California schools $120M solar project