User's Manual

Local GPS (RF GPS) Cable Chapter 3: Cable Descriptions

Table 3 -8 Local GPS Antenna Mounting Consider ations (Continued)

Description

tracking only one (1) GPS satellite. Motorola does not recommend tracking only one

(1) GPS satellite unless there has been an accurate site survey .

Place the Local GPS Head where RF obstructions of the sky are minimal. The

sky

includes everything to within ten (10) degrees of the horizon in all directions. RF

obstructions include buildings, towers, natural rock formations, snow , foliage, and

debris.

The mounting of the Local GPS head on antenna towers is not

recommended due to increased risk of damage due to lightning strikes. If

tower mounting is necessary the Local GPS head should mounted at the

lowest point possible and still maintain an unobstructed view of the sky .

Separate the Local GPS Head from other radiating sources. Excessive RF energy

can degrade the Local GPS Head’s ability to observe the GPS satellites. The Local

GPS Head receives on the GPS L1 frequency of 1575.42 MHz and incorporates

ﬁlters to minimize the effects of potential RF interference, however , strong radiants

can overwhelm the ﬁlters, thus degrading the units reception capability .

The Local GPS Head is rated for ambient air temperatures in the range -40 to +50

degrees C , and has ratings for humidity , shock, waterprooﬁng, UV light resistance,

vibrations, salt, fog, ESD , EMI, and altitude.

An RF gain of between +10 dB and +26 dB should be provided to the Local GPS

receiver antenna input. The GPS antenna supplied in the CGDSGPSKITF4NM50

kit provides a nominal gain of +25 dB. The total signal loss from the

CGDSGPSKITF4NM50 antenna output and Local GPS antenna input must be less

than 15 dB at 1.575 GHz.

3 -14 68P09277A59 -8

PRELIMINARY - UNDER DEVELOPMENT MA Y 2007