Model: MC-1-M (2U)
Doc. Ref. no. : m05/om/101
Issue no. 14
User’s Manual
Page 28 of 103
3. In-Line Antenna Amplifier
In-line amplifiers overcome signal attenuation in by amplifying the GPS signal. Use the in-line
amplifier for cable runs of 100 to 200 meter. Please contact a masibus Sales Representative for
information on how to extend the distance from the antenna to the receiver.
6.1.3
Verifying Antenna and Cable Operation
Please ensure that while doing below mentioned procedure for checking
antenna voltage/current while unit is in POWER ON condition, do not short
the antenna supply +5 Vdc and GND, in any case, failure of which will
damage the unit internal electrical supply.
This equipment is sensitive to Electrostatic Discharge (ESD). Observe all
ESD safeguards while using this equipment. Otherwise, there is danger that
the unit may get damaged through ESD.
6.1.3.1 Checking the Antenna Voltage
GPS Master Clock Model MC-1-M unit provides +5 Vdc to the GPS antenna though its Antenna
connector on unit rear panel, which is carried through the antenna cable. Nominal antenna current is
10 mA. Check the voltage at the antenna connector on the unit rear panel antenna connector.
Without the +5Vdc supply on antenna connector of unit, the antenna and GPS Master Clock Model
MC-1-M will not synchronize with the GPS satellites signal and can generate an GPS UNLOCK
alarm.
6.1.3.2 Power Supply Check
The Antenna Voltage test (mentioned above in section 6.1.3.1) actually tests the main power supply
voltage for all models of GPS Master Clock Model MC-1-M’s. This voltage should be between 4.9 and
5.1 Vdc.
6.1.3.3 Checking the Antenna Resistance
Checking the internal resistance of the GPS antenna is not as useful as verifying the antenna current
mentioned above in section 6.1.3.1. Antenna resistance measures several megohms with Multi-meter
probes at one polarity and less so if you change the Multi-meter probe polarity.
