NavCom RT-3020 Rev.F - Manual (Page 50)

RT-3020 User Guide – Rev. F
GPS Antenna Connector
The connector used on the RT-3020 is a TNC female,
labeled GPS ANT or GPS on the front panel of the
sensor as shown in Figure 5.
‡
The RT-3020 GPS connector provides
4.6 VDC, 50mA max to power the
antenna preamplifier. Do not
disconnect the antenna when the GPS
unit is powered on.
The system is supplied with 12ft (3.6m) of RG58/U
cable (P/N 94-310058-3012). The cable is fitted with
a right angle male TNC connector and a straight male
TNC connector respectively.
The cable length between the antenna and RT-3020
should not exceed 7dB loss at 1.575GHz for optimum
performance, though the system may tolerate up to
10dB of cable loss with minimal performance. Lower
elevation satellite tracking suffers the most with more
than 7dB insertion loss.
Table 8: Acceptable Cable Lengths
Cable
Type
Atten.
(dB) per
100 Ft.
Cable
Length
in Feet
Loss
in dB Atten.
(dB)
per
100 m
Cable
Length
in
Meters
Loss
in dB
RG-58C 19.605 36.00 7.06 64.32 11.00 7.08
RG-142 16.494 43.00 7.09 54.12 13.00 7.04
RG-213 9.564 74.00 7.08 31.38 22.50 7.06
RG-223 17.224 41.00 7.06 56.51 12.50 7.06
LMR600 3.407 207.00 7.05 11.18 63.00 7.04
LMR400 5.262 133.00 7.00 17.26 41.00 7.08
LMR240 10.127 70.00 7.09 33.23 21.00 6.98
LMR195 14.902 47.00 7.00 48.89 14.00 6.85
In-line amplifiers suitable for all GPS frequencies may
be used to increase the length of the antenna cable,
3-48