12 S&C Instruction Sheet 1074-510
Description
Antenna
Requirements
SpeedNet ME Radios have been designed to operate with the antennas listed below,
having a maximum gain of 3 dBd (5.15 dBi) or 10 dBd (12.15 dBi), respectively, and an
impedance of 50 ohms:
• Omni-directional fiberglass antenna: Antenex FG9023 or equivalent,
3 dBd (5.15 dBi)
• Uni-directional Yagi antenna: Kathrein TY-900 or equivalent,
10 dBd (12.15 dBi)
To reduce potential radio interference to other users, the antenna type and its gain
should be so chosen that the equivalent isotropically radiated power (EIRP) is not more
than permitted for successful communication.
Antenna/Cable
Requirements
Antennas for SpeedNet ME Radios must be installed by a qualified radio technician, in
order to comply with FCC Part 15 radiated power limits. Only antennas supplied by S&C
Electric Company may be used with the SpeedNet ME Radio.
The FCC mandates that Effective Isotropic Radiated Power (EIRP) may not exceed
+36 dBm. This is equivalent to a radio running at full output power (1 watt +30 dBm) with
a +6 dBi antenna. The antenna cable must have sufficient loss to bring the EIRP below
+36 dBm if a higher gain antenna is used. For example, using a +8 dBi antenna with a
radio transmitting at full power would result in an EIRP of +38 dBm. In this situation,
the antenna cable must provide
at least 2 dB loss in order to bring the EIRP into com-
pliance. SpeedNet ME Radios have configurable transmit power which can be selected
using the SpeedNet ME Radio client tool or by using IntelliTeam CNMS. Settings of
+30 dBm (default), +25 dBm, and +10 dBm are available. Any confirmed decrease
in output power should be considered when calculating E
RIP.
Tables 2 and 3 show the amount of loss incurred with several common antenna cables.
Table 2. Antenna Cable Loss
Cable Type
Loss per 100 Feet of Cable
LMR-400
3 .9 dB
LMR-600
2 .5 dB
LMR-900
1 .7 dB
Table 3. Antenna Cable Loss Examples with LMR-400 Cable
①
Antenna Gain
Length/Loss
ERP
+8 .2 dBi
60 feet/2 .3 dB loss
+36 .0 dBm
+10 .2 dBi
110 feet/4 .3 dB loss
+36 .0 dBm
+12 .1 dBi
160 feet/6 .2 dB loss
+36 .0 dBm
①
Assuming 1-watt output power from the SpeedNet ME Radio .
