HHT3 Operators Manual
General Information
Issue :No. 7b
Page : 2
Ref: HHT3-ASUM-7000
Copyright © 2018 IMT Ltd, trading as Vislink
WARNING: Do not incinerate batteries.
For safe disposal take to:
The local (council/authority) environmental waste site (in Europe in accordance with
the European Environmental directive).
For local battery disposal information, contact your local authority/recycling center.
The safe working distance from a transmitting antenna may be calculated from the
relationship:
D = √
In which:
D = safe working distance (meters).
PT = transmitter or combiner power output (watts).
GR = antenna gain ratio = anti log (gain dBi ÷ 10).
w = maximum allowed power density (watts/square meter).
The RF power density value is determined by reference to safety guidelines for exposure of
the human body to non-ionizing radiation. The guidelines adopted differ throughout the
world and are revised from time-to-time. For Vislink (Gigawave) use, a maximum power
density limit (w) of 1w/m² is applied when calculating minimum safe working distances.
WARNING: Any transmitting equipment radiating power at frequencies of 100 KHz and
higher, has the potential to produce thermal and athermal effects upon the
human body.
To work safely:
Operators should not stand or walk in front of any antenna, nor should they allow
anyone else to do so.
Operators should not operate any RF receiver or power amplifier with any of its
covers removed, nor should they allow anyone else to do so.
Antenna
Receiver Power
Type
Gain (dBi)
Gain Ratio
2W
4W
10W
30W
MINIMUM SAFE DISTANCE (METRES)
OMNI
4
2.5
1
1
1.5
2.5
HELIX
20
100
4
5.6
9
15.5
PARABOLIC
DISH
35
3,162
22.5
32
50
87
Table 1-1
Safe Working Distances for Receiving Devices
The RF Radiation Power Density limit figure recommended by Vislink (Gigawave) is based
on guideline levels published in:
P
T
. G
R
4
.w
