Dataradio Gemini/PD+, Installation Manual

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120 20120-211 Gemini
PD+
Installation Guide 15
4.3 Additional test details
4.3.1 TX Deviation
Gemini
PD+
is per unit factory-calibrated. Deviation values listed below serve as reference only.
Table 5 - TX Deviation
TX Deviation
Full Channel Units Special Channel Units Half Channel Units
xRC8FSK
UHF 800
xRC8FSK 800 US (NPSPAC) 900 US xRC8FSK UHF 800
43.2kb/s ±4.5 ±3.7 24.0kb/s ±2.9 ±2.8 21.6kb/s ±2.2 ±2.2
xRC4FSK UHF 800 xRC4FSK 800 US 900 US xRC4FSK UHF 800
32.0 kb/s ±4.3 ±3.6 19.2 kb/s ±2.1 ±2.1 16.0 kb/s ±1.9 ±1.9
25.6 kb/s ±4.0 ±3.7 14.4 kb/s ±2.3 ±2.3
DGFSK UHF 800 DGFSK 800 US 900 US DGFSK UHF 800
19.2 kb/s ±4.0 ±4.0 9.6 kb/s ±2.5 ±2.5 9.6 kb/s ±2.5 ±2.5
9.6 kb/s ±3.0 ±3.0 8.0 kb/s ±2.5 ±2.5 8.0 kb/s ±1.5 ±1.5
Tolerance is +5%, -10% for all bit rates.
4.3.2 GPS Test
About three minutes after ignition is turned-on, the PWR LED on the Gemini
PD+
radiomodem
front panel should flash in amber color at the rate of one pulse per second.
1
This indicates that the
GPS has acquired the sky position of a sufficient number of satellites to arrive at a ground posi-
tion 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 fol-
lowing 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) Following the antenna manufacturer’s recommended procedure:
A)
•
Test for continuity.
•
It is also suggested to compare electrical values obtained against those recorded in a
similar functional installation.
If found to be defective, replace with a known good active-type antenna.
B)
Make an antenna swap with a known working spare antenna.
3) If needed, connect the new antenna to the Gemini™ radiomodem and wait about three minutes
for the POSITION ACQUIRED indicator to start flashing on the Gemini
PD+
unit. If not, the
Gemini radio or its GPS receiver may be defective. Satellite signal strength may vary notably
because of location, time of day, atmospheric conditions etc…
1
Lit green and flashing amber for the 800MHz & 900MHz models under transmitter duty cycle limit.