Arbiter Systems 1200B, Руководство по эксплуатации

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4.4 Technical Details of GNSS Antennas and Cables 17
Physical Protection
When routing the antenna cable, protect it from physical damage, which may result from closing
doors, falling objects, foot traffic, etc. Also, when routing around corners, allow for sufficient bend
radius to prevent kinks. Extra length should be allowed at both ends of the cable to prevent tension
on the connectors, which could cause damage or failure. Extra length is useful as a service loop, in
the event that a connector needs replacement.
Do not stretch the cable midair over any appreciable distance without support. Cable
degradation or failure could result. Always leave a drip loop wherever the cable enters a structure,
to prevent water from entering the structure via the cable jacket. The maximum temperature
rating for the type of cable provided with the clock is 75
°
C (167
°
F). Exercise care when routing
the cable near sources of heat to avoid cable damage.
Adjacent Signals
Although the standard RG-6 style cable is triple-shielded and has excellent shielding properties, be
cautious when routing near high power RF sources or alongside cables carrying high power RF, such
as transmitter cables. In these applications, consider using RG-11 style cable (P/N WC0004900).
Its quad-shielded design provides even more isolation.
Antenna Power
The RF preamplifier within the antenna requires 5 Vdc at approximately 30 mA nominal for
operation. A power supply within the clock generates this voltage, which is applied to the antenna
via the two conductors of the coaxial antenna cable.
Avoid shorting the center conductor to
the shield of the coaxial cable as it may damage the preamplifier. Conversely, a high-resistance
connection or open circuit would deprive the preamplifier of power. Either a short circuit or open
circuit condition in the antenna cable will render the clock unable to receive satellite signals.
Prior to initial operation or if problems are suspected, go through the tests described in
Section 4.2.
Connection to Antenna
The male Type F connector on one end of the antenna cable mates with the female Type F connector
on the antenna. Avoid placing mechanical stress on the cable attachment to the antenna.
Connection to Clock
The male Type F connector on the opposite end of the antenna cable connects to the female Type
F connector on the rear panel of the clock.
User-Supplied Antenna Cables
Any RF cable meeting the requirements described above for loss ( < 21 dB at 1575.42 MHz) and
dc resistance ( < 15
W
total loop resistance) may be used with the clock. However, prior to using a
non-standard antenna cable, verify proper installation by reviewing Section 4.2.
For additional technical details concerning the GNSS, GNSS antennas and antenna cabling see
Appendix A, Technical Details and Specifications.