Model: MC-1-M (2U)
Doc. Ref. no. : - m05/om/101
Issue no. 14
Page 29 of 103
User’s Manual
6.1.4
Antenna Surge Suppressor
If GPS Surge Suppressor kit is available with purchase order, user should mount it in line with the
antenna cable. Additional information on grounding GPS antennas, and grounding in general, are
available from masibus Customer Support division (Kit P/N :m-LA-01).
6.1.5
Technical Details on GPS Antennas and Cables
Antenna Cable
Length and Loss Considerations
Standard Antenna Cable
The standard antenna cable assembly included with GPS Master Clock Model MC-1-M is constructed
using a 15-meters (50-foot) length of RG-6 type low-loss coaxial cable, terminated with male Type N
connector and BNC male connector. Optional lengths of RG-6 coax are separately available for longer
runs; see Table 4.2, Cable Data and Accessory Information.
Effects of Cable Parameters
To receive GPS signals and properly operate the clock, the type and length of the cable are important.
Due to their effect on specific parameters described in the following paragraphs, any changes to the
length and/or type of antenna cable should be made carefully. Damaged cables may also affect
performance.
Cable Delay
The velocity factor and the physical length of the cable determine cable delay. User has to enter delay
value according to antenna cable length.
For cable options, the delay is tabulated below. The formula for calculating
cable delay is:
Where:
T = Cable delay, in nanoseconds;
ƛ
= Cable length, in meters;
C = Speed of light (3 _ 108 meters per second);
Kv = Nominal velocity of propagation (0.85).
One nanosecond is added to the calculated value to account for the length and velocity factor of the short
connecting cable inside of the clock.
