Microwave Data Systems iNET 900 Series, Руководство пользователя, Страница: 142 / 180

134 MDS iNET 900 Series User’s Guide MDS 05-2806A01, Rev. E.1
900 MHz. The choice of cable will depend on the required length, cost
considerations, and the amount of signal loss that can be tolerated.
The tables below outline the minimum lengths of RG-214 coaxial cable
that must be used with common MDS omnidirectional antennas in order
to maintain compliance with FCC maximum limit of +36 dBi. If other
coaxial cable is used, the appropriate changes in loss figures must be
made.
NOTE: The authority to operate the transceiver in the USA may be
void if antennas other than those approved by the FCC are
used. Contact your MDS representative for additional antenna
information.
*Refer to Table 5-3 for allowable power settings of the transceiver for
each antenna type.
Table 5-1. Length vs. Loss in Coaxial Cables at 900 MHz
Cable Type
10 Feet
(3.05 m) 50 Feet
(15.24 m) 100 Feet
(30.48 m) 500 Feet
(152.4 m)
RG-214 .76 dB 3.8 dB 7.6 dB Unacceptable
Loss
LMR-400 0.39 dB 1.95 dB 3.90 dB Unacceptable
Loss
1/2 inch HELIAX 0.23 dB 1.15 dB 2.29 dB 11.45 dB
7/8 inch HELIAX 0.13 dB 0.64 dB 1.28 dB 6.40 dB
1-1/4 inch HELIAX 0.10 dB 0.48 dB 0.95 dB 4.75 dB
1-5/8 inch HELIAX 0.08 dB 0.40 dB 0.80 dB 4.00 dB
Table 5-2. Feedline Length vs. Antenna Gain*
(Required for Regulatory compliance)
Antenna
Gain (dBd) Antenna
Gain (dBi) Minimum Feedline
Length (Loss in dB)
EIRP Level @
Min. Length Maxrad Antenna
Part No.
Unity (0 dB) 2.15 dBi No minimum length +32.15 dBm Omni #MFB900
3 dBd 5.15 dBi No minimum length +35.15 dBm Omni # MFB900
5 dBd 7.15 dBi 3.1 meters (1.2 dB) +35.95 dBm Omni # MFB900
6 dBd 8.15 dBi 9.1 meters (2.2 dB) +35.95 dBm Yagi # BMOY8903
10 dBd 12.15 dBi 24.7 meters (6.15 dB) +35.25 dBm Yagi # Z941