Viper SC+™ IP Router for Licensed Spectrum PN 001-5008-000 Rev. C
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Yagi Antenna
At remote locations (not used as a Relay Point), a directional Yagi is generally recommended to minimize interference
to and from other users.
Vertical Dipoles
Vertical dipoles are very often mounted in pairs, or sometimes groups of three or four, to achieve even coverage and to
increase gain. The vertical collinear antenna usually consists of several elements stacked one above the other to
achieve similar results.
2.6.3.
FEEDLINE
The choice of feedline should be carefully considered. Poor quality coaxial cables should be avoided, as they will
degrade system performance for both transmission and reception. The cable should be kept as short as possible to
minimize signal loss. See the following table for feedline recommendations
Table 12 Transmission Loss (per 100 Feet)
Frequency Range
Cable Type
VHF
UHF
900 MHz
LMR-400
1.5 dB
2.7 dB
3.9 dB
1/2” Heliax
0.68 dB
1.51 dB
2.09 dB
7/8” Heliax
0.37 dB
0.83 dB
1.18 dB
1-5/8” Heliax
0.22 dB
0.51 db
0.69 dB
Outside cable connections should have a weather kit applied to each connection to prevent moisture. Feedline
connections should be routinely inspected to minimize signal loss through the connection. A 3 dB loss in signal strength
due to cable loss and/or bad connections represents a 50% reduction in signal strength.
2.6.4.
RF EXPOSURE COMPLIANCE REQUIREMENTS
Viper SC+ radios are intended for use in the Industrial Monitoring and Control and SCADA
markets. Each Viper SC+ unit must be professionally installed and must ensure a minimum
separation distance listed in the table below between the radiating structure and any person.
An antenna mounted on a pole or tower is the typical installation and in rare instances, a 1/2-
wave whip antenna is used.
Minimum Safety Distance
Antenna Gain
(cm @max power)
5 dBi
10 dBi
15 dBi
132 MHz (VHF)
123 cm
219 cm
389 cm
215 MHz (UHF)
122 cm
218 cm
388 cm
406.1 MHz
106 cm
188 cm
334 cm
900 MHz (Model # 1405098304)
66 cm
117 cm
208 cm
900 MHz (Model # 1405098504)
64 cm
115 cm
202 cm