57.6
± 3.37
Half Channel (UHF) 12.5kHz bandwidth
16.0
± 1.7
24.0
± 2.0
32.0
± 2.1
Wide Channel (700MHz) 50kHz bandwidth
64.0
± 5.3
96.0
± 6.2
128.0
± 6.5
Full Channel (800MHz) 25kHz bandwidth
32.0
± 2.4
48.0
± 2.7
64.0
± 2.9
43.2
± 3.3
NPSPAC Channel (USA - 800MHz)
16.0
± 2.4
24.0
± 2.7
32.0
± 2.9
5.3.2
GPS TEST
About three minutes after ignition is turned-on, the PWR LED on the GeminiG3 unit front panel should flash in b
link-
ing amber on green
color at the rate of one pulse per second (1pps). This indicates that the GPS has acquired the sky
position of a sufficient number of satellites to arrive at a ground position solution.
If the GPS has a good view of the sky and still has not generated any position solution within three minutes (it may
take up to 10 minutes or more if the sky view is partially blocked.), the following trouble-shooting procedures should
be undertaken to isolate the fault:
1) Disconnect the GPS antenna cable connector from the Gemini radio and check for + 5 VDC on the center pin of the
GPS antenna connector on the radio using a Digital voltmeter (DVM). If the voltage is present, do not reconnect
the cable and proceed to step 2.
2) With the DVM, measure resistance between the shell and the center conductor of the GPS cable, resistance should
be between 100 and 300 Ohms, if it measures open or short circuit the GPS antenna is either a passive antenna
which is the WRONG type, or a defective active antenna, replace with a known good active antenna.
3) Connect the new antenna to Gemini and wait about three minutes for the “PWR/PGM LED to start flashing at a rate
of 1 pulse per second
(amber on green)
on the GeminiG3 unit indicating that a position is acquired. If no position
acquisition occurs, the modem and/or its GPS receiver may be defective.
The User’s Interface GPS Web Pages are located starting at paragraph 4.7.4.
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