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R: Question on KLM Polarization Switching




----- Original Message -----
From: Jim Jerzycke <kq6ea@pacbell.net>
To: amsat-bb <amsat-bb@amsat.org>
Sent: Wednesday, August 14, 2002 3:47 AM
Subject: [amsat-bb] Question on KLM Polarization Switching


> Greetings, all.
>  I have an almost-new KLM 435-40CX with the CS-2 polarization switcher .
> The manual for the antenna shows how to mount and connect it, but has
> *NO* mention of which polarization it generates in the "Off" position.
> It appears to be connected in the configuration shown in the antenna
> manual. Does anybody remember (or have a manual) which polarization is
> "Off", and which is with +12VDC applied to the CS-2? I used it on Field
> Day, and was amazed how strong UO-14 was compared to my 11el linear Yagi
> at home. I'm guessing RHCP is the 'default'.
> Thanks!
> Jim  KQ6EA
>
>

Hi Jim KQ6EA,

Look please at the Assembly Pictorial 435-40CX page 6 of the manual

Put your self  on rear boom behind reflectors at the right side of page 6

You will look first the CS-2 switcher than the horizontal dipole and than
the vertical dipole.

The satellite is far away  going towards the left side of page 6

The horizontal and vertical dipoles are already mechanically spaced by
1/4 wavelenght in to free space on the boom so they are 90° out of phase
and no coax delay line outside the CS-2 switcher is needed to generate
almost one type of  circular polarization.

Looking at satellite from the reflector side the left side of the horizontal
folded dipole is connected to the center conductor of the coax cable
going to CS-2 switcher.

>From the same point of view the bottom side of the vertical folded dipole
is also connected to the inner conductor of the other coax line going to
CS-2 switcher.

Suppose now that the bottom end of the vertical dipole closest to the
satellite is at maximum positive or 6 o'clock for you

Since both conductors from CS-2 have the same lenght the left side of the
horizontal dipole is also at the maximum positive or 9 o'clock for you at
the same time

In order to get the same polarity of maximum positive the rear horizontal
dipole must rotate towards the satellite counterclockwise by 90° to go
from 9 o'clock to 6 o'clock and so in this delay condition the radiated
polarizazion in direction of the satellite is left hand or LHCP

Using an ohmeter you should only measure from the CS-2  and find  in
what relay position ON or OFF the above discussed  LHCP connection is
obtined..

Obviously the other position will be the RHCP and some form of delay line
should be included inside the CS-2 switcher for that.

Unfortunately i have only the manual on my hands  but not the antennas and
the above cames only from reasoning on how the vectors rotates to generate
circular polarization.

73" de i8CVS Domenico


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