3.4 BEAM: Antenna Beam Pattern
Product
Figure 4 BEAM Example Configuration
BEAM is a full screen cross-section format image showing range-averaged intensity in
azimuth and elevation coordinates.
The BEAM product is similar to a cross-section in that it shows a quasi-vertical slice of the
atmosphere. It is constructed from a PPI volume scan. The product is used primarily for
system testing and evaluation purposes, such as:
• Antenna beam pattern testing. Typically a radiator is on a tower a few km from the
radar. The radar is then scanned in sector or full PPI mode around the target using high
resolution (for example, <0.5°) spacing in AZ and EL. The transmitter is typically turned
o for this. The BEAM product can then be used to display the antenna response to the
radiator.
• Calibrated sphere measurement. Similar to above except the radar is radiating. The
sector scan is made about the calibration sphere which is typically suspended from a
tethered balloon. The resulting display shows the location and returned power from the
sphere. This can be used for full system calibration.
At near horizontal incidence (low elevation angles), the BEAM product is similar to a cross-
section. Since the product can be configured to average a range interval, the BEAM product
can give a picture of the weather or other targets in a spherical "slab" defined as a range,
azimuth and elevation interval. The cross-section on the other hand, attempts to show a
planar "slice" through the weather.
IRIS Product and Display User Guide M211319EN-H
34 RESTRICTED
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