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Steps 41, 42 and 43 are referenced in Figure 24.
41
Indicate if a polarization axis positioner is
required on the source antenna side of the anten-
na range. Provide the model number of any polar-
ization axis positioner that is to be used with this
system. There are two types of polarization axis
positioners: 1) a polarization positioner with a low
rotation speed and high position accuracy (used to
change the polarization of a source antenna by
rotating the source antenna 90 degrees), and 2) a
rotating polarization positioner with a high rota-
tion speed (10-30 revolutions per minute) and low
positioning accuracy (used to measure the ellipticity
or axial ratio of a circularly polarized antenna by
rapidly spinning a linear source antenna).
42
Indicate if a positioner controller and position-
er power supply are required. If existing units are
to be used, indicate their model numbers.
43
Indicate the length of polarization control
cables, if required.
Steps 44 through 48 are referenced in Figure 25.
44
Indicate the type of antenna under test (AUT)
positioner to be used with this system. If an exist-
ing positioner is to be used, indicate the model
number of this positioner. If a new AUT positioner
is required, indicate the axis required. An upper
azimuth axis is almost always required, an eleva-
tion axis is frequently required, and a lower
aximuth axis is seldom required.
28
45
Indicate if an existing model tower or roll axis
positioner is available or required for this system.
A model tower is sometimes used for mounting
antennas above the metal AUT positioner. Model
towers are usually made from non-conductive
materials.
46
Indicate if an existing positioner controller is
available or required for this system. If an existing
positioner controller is to be used, indicate its
model number.
47
Indicate if an existing positioner power supply
is available or required for this system. If an exist-
ing positioner power supply is to be used, indicate
its model number.
48
Indicate if existing positioner control cables
are available or required for this system, and the
length of these cables.
Near-field positioning systems
For near-field applications, Nearfield Systems, Inc.
(NSI) provides a wide variety of standard and cus-
tom robotic positioning systems that are all com-
patible with Nearfield application software. NSI
can be contacted at:
Nearfield Systems, Inc.
(310) 518-4277
fax: (310) 518-4279
e-mail: sales@nearfield.com
www.nearfield.com
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