User's Manual

154 Mercury Reference Manual 05-4446A01, Rev. C
cable at 900 MHz. The choice of cable depends on the required length,
cost considerations, and the acceptable amount of signal loss.
The tables below outline the minimum lengths of RG-214 coaxial cable
that must be used with common GE MDS omnidirectional antennas in
order to maintain compliance with FCC maximum limit of +36 dBi. If
other coaxial cable is used, make the appropriate changes in loss figures.
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 factory representative for additional
antenna information.
*Refer to Table 5-3 on Page 157 for allowable transceiver power set-
tings 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
15.2 dBd 17.4 dBi 50 meters (12 dB) +35.4 dBm Andrew
DB878G90A-XY