Re: NEC-LIST: CIRCULAR POLARISATION

Actually, like polarizations are "best," but it is an overstatement to say
they are *required*.

For example if you regularly work with both RHCP and LHCP antennas then you
could transmit/eceive to either using a linearly polarized antenna, such as
a dipole. However, there will be a polarization loss of ~3 dB when
exchanging signals between antennas.

- Mike

Executive Manager
Nanochron, LLC

> Zvi,
>
> Jasik is correct, like polarizations are required.
>
> If you transmit with an antenna with RHCP, you need to have an RHCP
receive
> antenna. The transmitted RHCP is going away with respect to the
> transmitter. If you point your right hand thumb in the direction of
> propagation the E-field will rotate to the right in the the direct of your
> curled up fingers. for RHCP. You may think that the receiver sees the
> transmitted signal as LHCP, but that is for the opposite direction of
> propagation, coming toward the receiver. This is still RHCP, not LHCP.
An
> RHCP receive antenna is still required.
>
> If that isn't good enough of an explanation, here is an analogy. Think of
a
> cork screw on which a ring is moving along in a helical motion. In order
> to transfer the ring to a second cork screw, you have to have the same
sense
> cork screw. A similar analogy could be a right handed screw is needed in
> order to drive it into a right handed hole, irriegardless of which end of
> the hole you are trying to drive it through.
>
> Example, now think of a helical antenna and how it is constructed.
Imagine
> creating a RHCP wave that is propagated toward a receing helix. It still
> needs to be RHCP. Does this make more sense now?
>
> I hope this explanation has helped,
>
> Roland Mueller
> -----Original Message-----
> From: zvi frank <zvi_f_at_mti-group.co.il>
> To: nec-list_at_gweep.ca <nec-list_at_gweep.ca>
> Date: Tuesday, December 24, 2002 9:40 AM
> Subject: NEC-LIST: CIRCULAR POLARISATION
>
>
> >I have a question which I thought was clear to me .When one transmits
with
> a
> >Right hand circular polarisation ,Should one receive with a left or right
> >hand circularly polarized antenna.? JASIK says like polarizations are
> >required which seemed logical to me till recently now I am not so sure???
> >Thanks for any comments.
> > Zvi
> >--
> >The NEC-List mailing list <nec-list_at_gweep.ca>
> >http://www.gweep.ca/mailman/listinfo.cgi/nec-list
> >
> >
> -----Original Message-----
> From: zvi frank <zvi_f_at_mti-group.co.il>
> To: nec-list_at_gweep.ca <nec-list_at_gweep.ca>
> Date: Tuesday, December 24, 2002 9:40 AM
> Subject: NEC-LIST: CIRCULAR POLARISATION
>
>
> >I have a question which I thought was clear to me .When one transmits
with
> a
> >Right hand circular polarisation ,Should one receive with a left or right
> >hand circularly polarized antenna.? JASIK says like polarizations are
> >required which seemed logical to me till recently now I am not so sure???
> >Thanks for any comments.
> > Zvi
> >--
> >The NEC-List mailing list <nec-list_at_gweep.ca>
> >http://www.gweep.ca/mailman/listinfo.cgi/nec-list
> >
> >
>
>
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