INSTALLATION
Antenna Cable
Requirements
(Need the S&C part numbers)
SpeedNet Radios must be installed by a professional, 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 Radios.
The FCC mandates that Effective Isotropic Radiated Power (EIRP) may not 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 compliance.
SpeedNet Radios have the ability to decrease transmit power. Any confirmed decrease in output
power should be considered when calculating EIRP.
The following table shows the amount of loss incurred with several common antenna cables.
Table 1. Antenna Cable Loss.
Type of Antenna Cable
Loss per 100' of Cable
LMR-400 3.9
dB
LMR-600 2.5
dB
LMR-900 1.7
dB
Table 2. Antenna Cable Loss Examples with LMR-400 Cable.
Antenna Gain
Cable Type/length/loss
EIRP
+8.2 dBi
60' LMR-400, 2.3 dB loss
+35.9 dBm
+10.2 dBi
110' LMR-400, 4.3 dB loss
+35.9 dBm
+12.1 dBi
135' LMR-400, 5.3 dB loss
+35.9 dBm
NOTE: Table 2 assumes 1 watt output power from the SpeedNet Radio.
1072-510
13
Antenna
Requirements
SpeedNet Radios have been designed to operate with the antennas listed below, and having a
maximum gain of 3 dBd (5.15 dBi) and 10 dBd (12.15 dBi) respectively. Antennas not included
in this list or having a gain greater than 3 dBd and 10 dBd are strictly prohibited for use with this
device. The required antenna impedance is 50 ohms.
Antenna List:
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 (e.i.r.p.) is not more than that permitted
for successful communication.
