Furuno FV-110, Руководство оператора

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Installation of the ADU
2-25
2.3.4 Alternative ADU cable
The allowed RF loss in the antenna cable is determined by the attenuators of the PSM and
VIM modules. The electronic design guarantees that minimum 20 dB RF loss @ 1700
MHz in the antenna cable will work, but typically an RF loss of about 25 dB will be
within the limits of the cable calibration. You can verify the cable attenuation margin with
the cable calibration. See
Cable calibration on page 5-11 for more details.
The DC-resistance loop of the antenna cable must be maximum 0.9 Ohm. This is to
ensure the power requirements from ACU to the antenna and to ensure the performance of
the system. Preferably choose one of the cable types listed in the table below.
Check the data sheet from the cable supplier that both the RF- attenuation and the DC-
resistance are kept within the maximum specified values:
• ADU cable RF-attenuation at 1700 MHz: max. 20-25 dB including connector.
• ADU cable modem-attenuation at 10 MHz: Max. 2 dB
ADU cable modem-attenuation at 36 and 54 MHz: Max. 4 dB
• ADU cable loop DC-resistance max: 0.9 Ohm.
Also ensure that the specified minimum bending radius is respected. If this is not the case,
the loss in the cable will increase. Check the documentation from the cable supplier.
Cable Type
Absolute maximum length
(m) Absolute maximum length
(ft)
RG223-D 25 m 80 ft
RG214/U 50 m 160 ft
S 07272B-05 95 m 310 ft
LMR-600-50 135 m 440 ft
LDF4.5-50
Andrew 300 m 980 ft
Table 2-7: ADU cable types and maximum lengths