Coaxial Cable; Cable Route; Coaxial Cable Installation - C-Nav IALA Hardware Reference Manual

C-Nav Hardware Reference Guide

Coaxial Cable

Proper installation of coaxial cables is important to ensure successful communication between
the antenna and the GNSS Receiver.

Cable Route

When choosing a cable route for coaxial cable, consider the following:
 Avoid running coaxial cable across, or parallel too power cables and high power RF
cables.
 Ensure that the cable route is free of and sharp edges or places where the cable could
become pinched or damaged in any way.
 Determine the manufacturers specifications for the coaxial cable in use. This should
include: impedance, diameter, attenuation in dB/100ft and dB/100m at the applicable
frequency, velocity of propagation and the minimum bend radius of the cable.
 Ensure the cable does not exceed the recommended minimum bend radius suggested
by the manufacturer.
 Ensure there is sufficient space at the cable entry point to the bulkhead as to not
damage the connector during installation.
 Measure the length of the cable route and refer to Table 2-1 for acceptable cable lengths
in relation to attenuation loss at the frequencies in use. For best performance, do not
allow more than 7dB (18dB for C-Nav1000) of cable loss between the antenna and the
receiver; lower elevation satellite tracking suffers the most with more than 7dB insertion
loss.
 In-line amplifiers suitable for all GNSS frequencies may be used to increase the length of
the antenna cable, but care should be exercised that tracking performance is not
degraded due to multiple connections, noise from the amplifier, and possible ingress of
moisture and dust to the in-line amplifier. In-line amplifier or splitter devices must pass
DC power from the receiver to the antenna, or source the appropriate voltage and
current to the antenna In-line amplifiers may also over-saturate the receiver front-end if
improperly used.

Coaxial Cable Installation

1. Prior to connecting the coaxial antenna cable to the antenna, ensure that all connections
are free of dirt and other debris. Apply silicone grease to the connector threads and wipe
off any excess, ensure not to get any lubricant on the contact. Connect the coaxial cable
and tighten firmly. Wrap the connection with self-amalgamating tape or another weather
sealant such as Coax-seal to prevent water ingress.
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