36
www.behnke-online.com
GB
Instructions Video 2-wire transmitter and receiver
GB
General Information
6.3. Type of Cable
Use a cable of the UTP type (unshielded twisted
pair) cat. 5 (according to the T1A/EIA 568A
standard and as defined in ISO / IEC 11801). This
cable enables long distance transmissions as
well as transmission of multiple video signals
and / or telemetric signals (maximum 4) via one
cable. It is also possible to use TWT pairs and
TWR / TWRB repeaters to achieve longer dis-
tances transmission; in this case, the maximum
one-way distance should not exceed 1.500 m,
and you should not use more than one repeater
to maintain the video signal quality in as good a
state as possible.
* The cables with 100 ohms are the most commonly used
** Most commonly used diameter
Impedance
1 - 100 MHz
Attenuation
(maximum)
N.E.X.T.
(minimum)
Resistance
(maximum)
Diameter
100 ohms ±
15 ohms*
21 dB/km
at 1 MHz
62 dB/km
at 1 MHz
192 ohms/km
24 AWG**
43 dB/km
at 4 MHz
53 dB/km
at 4 MHz
65 dB/km
at 10 MHz
47 dB/km
at 10 MHz
Definitions
Attenuation: A value stated in dB, which stands
for the function of a frequency describing the
amplitude signal being reduced along the
conductor. The lower the attenuation, the longer
the possible distance for transmission.
N.E.X.T.: Near-End Crosstalk; a value stated in
dB, which stands for the function of a frequency;
this function predicts to what extent one signal
causes interference on another signal. The
higher the N.E.X.T. value, the lower the inter-
ference the one signal causes the other signal.
AWG: American Wire Gauge, the American
system to measure cable diameters. E.g.
24 AWG corresponds to a diameter of 0.5 mm.
The following table provides an overview on
maximum attainable distances with one or mul-
tiple pairs for colour and black-and-white video
signal transmission with a cable type UTP 4 x 2 x
24 AWG cat. 5 100 ohms:
Colour
black/white
Maximum distance 1 video pair
1,500 m
2,000 m
Maximum distance 4 video pairs
1,000 m
2,000 m
