Re: [amsat-bb] Whose Right and Whose Left--CP REPLY

["Ben" <b-fisher@xxxxxxxx>]

Yes Howard, it is the picture I have been referring to .

One of three things is going on.

1. The picture is improperly defined
2. The definition of Right and Left hand is backwards
3. The cross yagi behaves differently than I understand

First of all. From the perspective of standing behind an antenna that is
transmitting a RHCP signal, and if slowed down to the point one could see
it. It would be rotating cw as it travels away from the antenna. Now as the
signal is being received by another fellow who is standing behind his
antenna with his it pointed at the first fellow. He would see the signal
entering his antenna rotating CCW among his elements. NOT CW. both antennas
are RHCP. If the second fellow transmits than his signal would be rotating
CW as it travels back to the first fellow. This is and remains contrary to
the definition of the antenna in the picture.
73
Ben K9BF

>> > In the picture the horizontal
> > yagi is closest to him and the vertical one is 1/4 wave length ahead or
in
> > front of the horizontal one. The antennas are feed in phase. The high
side
> > of the horizontal antenna is to the right of the boom and the high side
of
> > the vertical antenna is above the boom. If a CP signal with the same CP
as
> > the antenna is being received, it first hits the forward yagi than
rotates
> > CW 90 degrees and intersects the second yagi. If one were to transmit
from
> > the same antenna the signal would be rotating CCW from the perspective
of
> > one standing behind the antenna.
>
> You might be referring to http://www.g6lvb.com/images/rhcp.jpg, which
sounds
> the same as your description, although I didn't go into any details. As
they
> say, often a picture tells a thousaned words.
>
> The way I look at it is that to consider how an imaginary point in front
of
> the antenna will see it from the same point of view as the camera's in the
> picture, with our antenna transmitting. If fed in phase the vertical
> wavefront is received first and then the horizontal wavefront, thus
forming
> a right-hand screw. If you turned the horizontal driven element round 180
> degrees, it would be LHCP.
>
> 73 Howard W7/G6LVB
>

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