Lars Thrane LT-3100, Руководство пользователя и инструкция по установке

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LT-3100 User & Installation Manual Rev. 1.06 Interfaces
Lars Thrane A/S www.thrane.eu Page 36 of 155
LT-3130 Antenna Unit
The LT-3110 Control Unit and the LT-3130 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 are not providing enough information about the DC
resistance, in which cases, the cable manufacture must be approached to obtain this
information.
Lars Thrane A/S has calculated the maximum allowed cable lengths with two coaxial cables as illustrated in
Table 6. The two coaxial cables are FF195LSFROH (~RG-58) and FF400LSFROH (~RG-214/LMR400).
The cable lengths calculated in Table 6 are obtained by using the maximum DC resistance [ Ω ] from Table 5
and compare these maximum DC requirements with the actual DC resistance [ Ω /km] of the specific coaxial
cables. The FF400LSFROH and FF195LSFROX total DC resistance numbers are listed in Table 7 on page 37.
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
12 VDC 1.7 Ω
24 VDC 5.5 Ω
Table 5: DC Coaxial Cable Requirements
Maximum Coaxial Cable Length
Cable Type 12 VDC Supply 24 VDC Supply
FF195LSFROH (4.9mm) 41 m 135 m
FF400LSFROH (10.3mm) 154 m 500 m
Table 6: Maximum coaxial cable length (cable examples)