S&C Instruction Sheet 1074-510 11
Operation
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 chosen so 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 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 36 dBm. This is equiva-
lent 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 to bring the EIRP
into compliance. SpeedNet ME radios have configurable
transmit power that can be selected using the SpeedNet
ME radio client tool or by using the IntelliTeam® CNMS
Communication Network Management System. Settings of
+30 dBm (default), +25 dBm, and +10 dBm are available.
Any confirmed decrease in output power should be con-
sidered when calculating ERIP.
Tables 2 and 3, and Tables 4 and 5 on page 12 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
-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 (18 m)/2.3 dB loss
+36.0 dBm
+10.2 dBi
110 feet (34 m)/4.3 dB loss
+36.0 dBm
+12.1 dBi
160 feet (49 m)/6.2 dB loss
+36.0 dBm
①
Assuming 1-watt output power from the SpeedNet ME radio.
