Lars Thrane Iridium Certus 200, User & Installation Manual

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LT-4200 User & Installation Manual Rev. 1.00 Interfaces
Lars Thrane A/S www.thrane.eu Page 30 of 128
LT-4230 Antenna Unit
The LT-4210 Control Unit and the LT-4230 Antenna Unit must be connected using a coaxial cable. Both the
control unit and the antenna unit have a N connector (female) mounted. This section will specify the
requirements to the coaxial cable. The RF and DC requirements are specified in Table 4 and Table 5.
In most cases it will be the DC resistance that will determine the maximum length of the coaxial cable. It is
important to note that the input voltage of the control unit is important for the length of the coaxial cable
that can be used.
NOTE : The DC coaxial cable resistance that is listed in Table 5 and used to calculate the maximum
cable length is the sum of the DC inner conductor resistance and the DC outer conductor
resistance. Some data sheets do not provide enough information about the DC resistance,
in which case, the cable manufacturer must be approached to obtain this information.
Lars Thrane A/S has calculated the maximum allowed cable lengths with one coaxial cable as illustrated in
Table 6. The coaxial cable being FF400LSFROH (~RG-214/LMR400).
The cable length calculated in Table 6 are obtained by using the maximum DC resistance [ Ω ] from Table 5
and compare the maximum DC requirements with the actual DC resistance [ Ω /km] of the coaxial cable. The
FF400LSFROH total DC resistance numbers are listed in Table 7 on page 31.
RF Coaxial Cable Requirements
Requirement Specification
Cable impedance 50 Ω
Maximum signal loss 45 dB/100 m @ 1.5 GHz
Table 4: RF Coaxial Cable Requirements
DC Coaxial Cable Requirements
Power Source Maximum DC Resistance
24 VDC 1.65 Ω
Table 5: DC Coaxial Cable Requirements
Maximum Coaxial Cable Length
Cable Type 24 VDC Supply
FF400LSFROH (10.3mm) 150 m
Table 6: Maximum coaxial cable length (cable examples)