Chapter 1 Introduction
This manual covers the installation procedures for ASTRO APX mobile and motorcycle radios with 
O2, O3, O5, O7 and O9 control heads, and accessories required to complete the radio system. The 
radio system consists of a control head, radio, antenna, microphone, speaker, cabling, Universal 
Relay Controller (URC), and accessories.
NOTE: APX Mobile high power do not support motorcycle radios.
1.1 Mobile Radio Description
1.1.1 Dimensions
When installing the radio, plan the installation carefully and leave additional room in the rear of the 
radio for cabling and accessory connections. Allow additional room in the front of the radio for 
access, controls, and cabling for remote mount and to the sides of the radio so that you can access 
and install the trunnion screws/wing screws.
NOTE: The measurement unit used in Figure 1-1 to Figure 1-20 is millimeter.
Figure 1-1.  Front View of O2 Control Head Attached 
to APX 8500
Mid Power Dash Mount Transceiver and Trunnion
Figure 1-2.  Side View of O2 Control Head 
Attached to APX 8500 
Mid Power Dash Mount Transceiver and Trunnion
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