Table of Contents
VideoWave 1.4GHz
Operation and Installation Instructions
System Description
3
Survey and Installation Guide
4
Antenna Mounting
8
Antenna Types
8
Transmission Distance
9
Wireless Telemetry
10
External Weatherproof Enclosures
11
Survey Kit
12
Technical Notes
13
Fault Finding
15
VideoWave Specifications
16
The VideoWave system is a professional quality system designed for sending
composite NTSC or PAL video signals. All products comply with the R&TTE
Directive 1999/5/EC. Models are available with various power outputs for licensefree operation in most European countries.
Due to the license-free operation of these products, there is no guarantee that
interference will not occur in a particular installation.
RDT does not assume any responsibility for the use of the products described. No
product patents are implied and RDT reserves the right to change the said
products without notice at any time.
2
System Description
Survey and Installation Guide
The VideoWave Wireless Video Transmission is a professional system designed for
sending composite NTSC or PAL video signals using 1.4 GHz wireless technology.
Before carrying out installation, it is important to bench test and familiarize yourself with the
equipment. This manual will help with antenna choice, transmission performance,
achievable distance etc.
Note: The longer the radio path the more critical details of installation become.
Figure 1 - Transmitter connections
Bench Test
SMA Antenna Connector
The Videowave system is supplied as standard with an ANT2350, Patch antenna. These
will be sufficient for testing and for use over short to medium distances (see table on Page
9).
Before testing the VideoWave equipment, connect the camera to be used, directly to the
monitor with a 75 ohm cable and check for correct operation.
Note: Do not power the transmitter without an antenna connected. Always disconnect
power to the transmitter before connecting the antenna. Failure to do so may damage the
unit.
Fit the antenna to the VTX unit (transmitter) and connect the power using the 12V unit
supplied (or the mains supply in an SE version). The LED will show RED indicating 'power
on'. Now connect the camera to the video input. When the camera is powered the 'on'
LED will change to GREEN, indicating the presence of a video signal.
Note: The unit will not transmit until it detects a valid video input.
12V DC Adaptor
LED On/Video
BNC Video Input
Fit the antenna to the VRX unit (receiver) and connect the power. The LED will light RED
to show 'power on'. Connect the video output to the monitor. When the camera is turned
on, the LED will change to GREEN, indicating a video signal is being received. The picture
should appear on the monitor and be clear with no distortion.
Figure 2 – Receiver connections
System Performance
SMA Antenna Connector
The VideoWave functions in exactly the same way as standard broadcast TV
transmissions, but on a much lower signal strength. TV aerials are normally installed as
high as possible to give the clearest signal path and achieve good reception. In most cases
if the external TV aerial is disconnected and replaced with a small indoor aerial, the
reception becomes poor. In the same way, VideoWave will always perform best by
adopting the same principle. Terrain, antenna height and signal strength will always be the
deciding factors in achieving good communications.
In an ideal installation 'LINE-OF-SIGHT' between the transmitter and receiver will give
optimum results (see Technical Notes). Obstacles blocking the line of sight will reduce
transmission distances and affect picture quality. The video signal may pass through walls
of brick or wood but metal objects will almost certainly block the signal; the denser the
obstacles the greater their effect.
Note: Metal objects near or directly behind the antennas may also have an adverse effect.
If possible carry out a survey to establish good communications before final installation
12V DC Adaptor
LED On/Video
BNC Video Output
3
4
Site Survey
It is advisable to carry out a survey to establish a good radio path prior to installation. This
will help with the positioning of the equipment and choice of antenna. Your distributor
should be able to assist with information and may be able to provide a Survey Kit and
antennas.
Before commencing a survey, measure or estimate from a map, the straight-line distance
between the two sites. From the tables on page 9, check which type of antenna would be
needed to cover the required distance. Visit the sites to see if there is a suitable location
for equipment and the antennas, normally on the roof of the building. It should also be
possible to see if there is a reasonable line-of-sight between the two locations or if there are
any significant obstructions (see Technical Notes). A pair of field glasses may be useful if
the sites are some distance apart.
Make a temporary installation of a camera and transmitter. Note: battery-operated
equipment is available for this purpose. Position the antenna and leave the equipment
running. At the receive site, set up the receiver and monitor. Position the antenna and
adjust its position to get the best picture quality. If the picture quality is not good, try
moving the antenna to other locations. Performance will be affected by obstructions or
metal objects nearby. Even the antenna mounting pole can cause a problem if the antenna
is not correctly mounted clear of the pole. For longer distances, it may be necessary to use
a high gain antenna on the receiver site.
Note: High gain antennas are directional and must be aimed at the transmission site and
then adjusted by rotating until maximum signal strength is achieved. The POLARISATION
of both antennas must match. For example, if the transmitting antenna is vertical then the
receiving antenna must also be vertical.
If the signal strength is too low it may be increased by raising the height of the transmit
antenna, receive antenna or both. Care must be taken, however, because there will be a
loss of signal in the cable and connectors. For the actual installation, a good quality lowloss cable should be used between the antenna and the VideoWave units (i.e.LMR400).
Alternatively, the VideoWave unit can be housed in a weatherproof enclosure and mounted
on the pole near the antenna.
If the picture quality is poor, even with reasonable signal strength, this may be due to
interference. Remember that this is a license free band and other users could be
transmitting in the area. If interference is suspected, try turning off the transmitter and
checking the LED on the receiver. This should be RED and not GREEN or flickering
RED/GREEN. Also look at the monitor, which should just show a clean screen with no
patterning. If there is interference, try moving the antennas.
5
Figure 3
Transmitter
Video Camera
Receiver
To 12V DC
Adaptor
Video Monitor
To 12V DC
Adaptor
Figure 3 shows the most common connection diagram for setting up a simple wireless
video link using the VideoWave system.
Installation
For this section, it is assumed that the equipment has been bench tested, is working
correctly and that a site survey has been completed. If not, carry out these tests before
beginning the installation.
Transmitter
Start by installing the transmitter in the required location. The transmitter can either be
located inside or outside, if it is housed in a suitable weatherproof enclosure. (See page
11)
Connect the antenna. For short-range operation the standard Patch or ½ Wave whip
antenna can be used, fitted directly to the transmitter. For greater distances a Dipole or
12dB patch should be selected. These will require external mounting on a suitable pole
(see page 7).
Note: 1/2 Wave Whip antennas are not weatherproof and therefore not really
recommended for external use.
Generally, the higher the antenna, the better the radio performance. It should be noted
however that there will be a significant loss of signal in the antenna cable if it is too long.
The recommended cable is LMR400, which has a loss of approximately 0.2dB per metre.
There will also be a small loss of approximately 0.2dB for each connector.
Using these figures as a guide, the recommended maximum length of antenna cable is
about 5 metres, which equates to a loss of about 1dB. This will reduce the effective
radiated power, but will have little effect on the actual distance achieved. Raising the
antenna height has a much greater effect than changing the radiated power.
If it is necessary to mount the antenna even higher, to clear a building for example, then a
higher gain antenna can be used to compensate for the loss in the cable. If possible, it may
be better to house the transmitter in a weatherproof enclosure and mount the unit close to
the antenna.
Install the camera in the required position and connect to the transmitter using a 75 ohm
coax cable. Connect the power to both units.
Before leaving the transmitter site, if possible, check that the unit is working correctly using
the receiver unit connected to a monitor. It may be necessary to adjust the camera view or
lens iris to obtain the clearest picture.
6
Receiver
Antenna Mounting
Installation of the receiver unit is basically a repeat of the transmitter installation.
The antenna selection will depend on the distance from the transmitter site and the results
of the site survey.
When the antenna is in position, before finally tightening the fixings and securing the cable,
connect the receiver unit and connect a monitor to the receiver. Check the picture on the
monitor. Again adjust the antenna position if required to obtain the best possible picture.
Because of reflections and multi-path, small movements of the antenna can have a
significant effect.
If a high gain antenna is being used, aim the antenna in the direction of the transmitter.
Make sure that the polarization of the two antennas match. Using the picture on the
monitor, rotate the antenna in the horizontal plane until the best picture is achieved.
Once the best results have been obtained fix all the equipment in position.
Note: As with the transmitter installation, cable lengths should be kept to a minimum to
reduce losses. Again, consider mounting the receiver unit close to the antenna in an
external
General
It is important that antennas are mounted correctly and securely. Remember that on a high
pole, although the antennas are relatively small, there will still be a considerable wind
loading. If in any doubt, contact a qualified aerial rigger.
It is essential that the polarization of the transmit and receive antenna is matched.
Make sure that all connections are weatherproof. This can best be achieved by covering all
connectors with a layer of self-amalgamating tape. Also make sure that cable entries to
buildings are well sealed with mastic.
Figure a
Figure b
Figure c
Figure d
The above diagrams show some typical examples of antenna mounting.
a. Not recommended. The mounting pole will have an effect on the antennas
performance and could cause reflections.
b. This is the preferred arrangement where the antenna is clear of the
mounting pole.
c. Not recommended. Although in this position the antenna may work,
especially if the radio path is away from the wall, the proximity of the wall can
cause adverse effects. Many walls, for example, have steel reinforcing or even
metal cladding.
d. This is the preferred arrangement with the antenna clear of the building. A
small pole mounted on ‘A’ brackets may be required to clear the roof overhang,
as shown.
Antenna Types and Performance
Any of the following antennas may be used in combination to give the best possible link
quality. Always make sure that the polarity is matched i.e. both vertically polarized.
High gain antenna, such as the 12dB Patch, should only be used on the receiver. A small
amount of gain is acceptable on the transmitter to compensate for cable losses providing
the ERP (maximum output power at the antenna) does not exceed the limit.
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8
Wireless Telemetry
Telemetry for controlling PTZ cameras etc. cannot be transmitted directly over the
VideoWave but requires the addition of a Radio Modem to transmit the data. The RM96XX
series of modems is designed for use in the license free bands and is approved for all
European countries.
The modem is compatible with most commercially available video telemetry units ( see
table below).
7.5cm
10cm
10cm
ANT2350 3dB patch
(standard issue)
10cm
ANT0002 ½ wave whip
(TNC connector)
ANT0003 ½ wave whip
(SMA connector)
13cm
Installation
The RM96XX modem can be supplied separately or mounted alongside the VideoWave
unit in an IP67 enclosure. (SED versions) Because the modem relies on a good radio path,
the installation procedure and test methods should be basically the same as for
VideoWave. It is always best to carry out a survey to ensure good signal strength.
The 96XX modem will normally operate over a much greater distance than the VideoWave
system, therefore if a suitable site is found for the VideoWave, there should be no problem
with the modem link. Care must be taken in selecting the correct antenna and the antenna
installation. Follow the same principals as for VideoWave.
The data antenna should be mounted a minimum of 3 metres apart from the video antenna
to avoid interference.
See the RM 96XX User Manual, supplied with the unit, for details on modem operation and
set-up. Application notes are available giving details of the modem settings for most of the
common telemetry systems.
Telemetry Protocols Supported:
50cm
18cm
ANT0005-CAB Dipole
with 3m cable
ANT2351-CAB 12dB patch
Transmission Distances in Metres (Line-of-Sight)
Antenna
Description
Distance
ANT2350
ANT0002
ANT0003
ANT0005-CAB
ANT2351-CAB
3dB patch (standard issue)
½ wave whip (TNC connector)
½ wave whip (SMA connector)
Dipole with 3m cable
12dB patch
1000 -1500m
800m
800m
1000 – 1500m
2000 – 4000m
9
Telemetry Manufacture/Protocol
RS485/
RS232
Baud
Rate
Data
Bits
Stop
Bits
Parity
American Dynamics (sensormatic)
RS485
4800
8
1
None
Baxall Baxnet
RS485
9600
8
1
None
BBV RS485
RS485
9600
8
1
None
BBV 20mA
RS232
1200
8
1
Even
Conway
RS485
9600
8
1
None
Dennard dome
RS485
9600
8
1
None
Dedicated Micros DS2 remote keyboard
RS232
19200
8
1
None
Honeywell Orbiter
RS485
9600
8
1
None
Honeywell KD6
RS485
9600
8
1
Even
Honeywell HRHD remote keyboard
RS485
9600
8
1
None
Mark Mercer
RS485
9600
8
1
None
Bewator/Molynx
Panasonic
RS485
RS485
9600
4800, 9600
8
8
1
1
Even
None
Pelco D
Pelco P
RS485
RS485
2400
4800
8
8
1
1
None
None
Pelco P (9600)
RS485
9600
8
1
None
Vicon
RS485
4800, 9600
8
1
None
Videoswitch Vi series DVR
RS485
9600
8
1
None
Vista DVR remote keyboard (Baxnet)
RS485
9600
8
1
None
Vista Powerdome
RS485
9600
8
1
None
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IP67 Weatherproof Enclosures
Videowave Survey Kit
Standard Enclosure for VideoWave Transmitter or Receiver
Model VTX1394SE or VRX1394SE
The enclosure is supplied
with a Top antenna
connector, Bulkhead Plate
and internal cables.
The top connector is a TNC
connector suitable for direct
connection of a ANT0002 or
ANT2350 antenna.
The bulkhead also has cable
glands to seal the video and
power input leads.
Dual Enclosure for VideoWave Transmitter or Receiver and Radio Modem
Model VTX1394SED or VRX1394SED
The enclosure is supplied
with Top antenna
connectors, Bulkhead Plate
and internal cables.
On the top there is a BNC
for
the
data
antenna
(modem) and a TNC for the
video. The Bulkhead has
two 'N' Type connectors for
mounting remote antennas
via an extension cable.
The bulkhead also has cable
glands to seal the video,
data and power input leads.
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Features
1.4GHz, 2.4GHz and 5.8GHz versions
available
Licence exempt operation
Compact & portable
Low power 12V operation
4” LCD display
Video input/power indication
Received signal strength indication
Contents
1 x Flight case
1 x Videowave transmitter
1 x Videowave receiver
2 x ½ wave whip antenna
1 x Monitor
1 x Tripod/clamp
1 x 12V battery 2.1Ah
1 x 12V battery 4Ah
1 x Battery charger
1 x 12V power supply & mains lead
2 x 12V power leads
1 x Antenna ext. cable & mounting clip
1 x Video lead (BNC to phono)
1 x BNC elbow adapter
Brief Description
The Videowave Survey Kits are ideal for conducting site tests/surveys prior to installation of
fixed radio links. An adjustable mounting bracket on the transmitter enables simple fixture
to a wall or other surface, or freestanding use mounted to the 4Ah battery. The receiver
and 4” monitor may be operated in the case, or out of the case using the adjustable
mounting bracket and versatile tripod/clamp. The tripod/clamp may alternatively be used to
support a video camera (not supplied). Low power 12V operation ensures versatile power
options with the high capacity batteries and mains PSU supplied, and LED’s for indication
of power, video input, and received signal strength enable simple set up for maximum
performance.
Note: Camera is Not included.
12
Technical Notes
Propagation/Distance
For any radio link, the distance that can be achieved between sites depends on a number
of factors, the main ones being; the output power, the antenna height (above ground), the
type of terrain and ‘line-of-sight’. Line-of-sight means how clear the path is between the
two antennas, whether there are any obstructions and how dense these obstructions are.
The major effect on distance however, is the height of the antennas above ground. The
basic relationship between signal strength, antenna height and distance is given in the
following formula:Signal strength : (TX antenna height)² x (RX antenna height)²
(Distance)4
From this formula it can be seen that if the distance doubles, the signal strength decreases
to one sixteenth. In other words, to increase the distance from 1 Km to 2 Km, requires an
increase in signal strength of sixteen times. It can be seen therefore that increasing output
power has a limited effect on distance.
Increasing the antenna height however, has more effect. If the antenna height (above
ground) is doubled, the effective signal strength increases four times. This is true for either
the transmit or receive antenna so by increasing the height of both a significantly greater
distance can be achieved.
Clear line-of-sight
When we refer to a clear line-of-sight for radio signals, this is different to a visual line-ofsight. You may be able to see the transmitting antenna from the receiver site, but this does
not necessarily mean a good radio path.
It should also be remembered that radio signals at 1.4GHz will not normally pass through
buildings and they will be severely attenuated by vegetation, such as trees.
Even with a clear line-of-sight (as defined above) the ground, or nearby buildings, can
cause reflections. These reflected signals will also arrive at the receiver and can interfere
with the direct signal causing a reduction in signal strength or lost data.
Reflections
The best possible performance and therefore distance, will be achieved if there is perfect
unobstructed line-of-sight between the two sites ‘A’ and ‘B’. Even in this situation however
there is almost certain to be some degree of reflections from the ground or nearby
structures.
These reflections will have an effect on the signal strength and the final picture quality
obtained. It is useful therefore to understand the basic principals of a radio link and the
effect of reflections. The most common reflection is from the ground although other
structures, buildings etc. will have a similar effect. The reflections from these other
structures are less predictable because they depend on the shape of the structure,
construction material etc.
Consider a radio path between site ‘A’ and ‘B’ with each antenna 10 metres from the
ground. Assuming good line of sight, there will obviously be a path directly between the two
antennas, drawn as a straight line on the diagram. There may also be one or more paths
that are reflected from the ground and reach site ‘B’ indirectly via a point on the ground, ‘X’.
Obviously the distance A-X-B is longer than the direct route A-B. The receiver at site B will
receive a direct signal and a reflected signal via point X.
A radio signal transmitted between two antennas will spread out forming an elliptical shape
that is widest at the mid distance between the two antennas. The area within this ellipse is
known as the Fresnel Zone and any obstructions within this zone will cause an obstruction
and interference to the signal path.
TX
Fresnel Zone
Radius
Note that this Fresnel Zone is three-dimensional and has both height and width. The
maximum radius of the beam, at the centre, increases with the distance between the two
antennas. As a guide, at 1.4GHz the radius for a particular signal path is:
1Km signal path
2Km signal path
5Km signal path
5 - 6Mtr radius
8 - 9Mtr radius
12 - 14Mtr radius
This means for example, that if the link is 2Km long, the antennas must be at least 8 to 9
metres above the ground and above any building or obstruction. There must also be the
same 8 to 9 metres clearance to either side.
13
RX
The effect of this reflected signal depends on its strength and the difference in length
between A-B and A-X-B. If the difference is a multiple of the wavelength ( approximately
21.4cm for 1394MHz ) the reflection is 180º out of phase and will reduce the received signal
strength. In fact if both signals were the same strength they would cancel and no signal
would be received.
Because at these frequencies the wavelength is quite short, even a small adjustment in
antenna height can affect the path length of the reflected signal and so change the received
signal strength. By raising the antenna gradually it will cycle through a regular pattern of in
phase and out of phase signals giving a corresponding pattern of reduced and increased
signal strength.
The reflected signal will show up as ghosting on the monitor. Occasionally this may be
seen in adverse weather conditions when a signal may be reflected from rain, snow, dense
cloud or fog.
14
Interference
Because the 1.4GHz frequency band is an unlicensed public access bands, there is no
control on other users. It is therefore possible that another user could be operating on the
same frequency in your area. If this is suspected, turn off the transmitter and check that the
LED on the receiver is RED and does not flicker GREEN. Also check the monitor, which
should be clear of any moving patterns, ghosting etc.
If there are other users it may be possible to avoid interference by repositioning the
antenna. A directional antenna such as a Yagi may also reduce the effect.
Fault Finding
Problem
Solution
No LED's illuminated Applies to Tx and Rx
units)
Check 12V power supply. The RED LED
should light to indicate 'power on'.
Venetian blind effect
Incorrect voltage from power supply.
Should be 12V
Low or no signal strength on VRX
Check that the VTX is transmitting:
RED LED: power on - not transmitting
GREEN LED - transmitting
Snowy or grainy picture
Weak signal. Check number of GREEN
LED's on VRX unit. See pages 5 and 13
regarding antenna height and location.
Picture rolling or tearing
Reflections. See page 14
Check output voltage from camera. it
should be nominally 1V p-p
Specifications
General
Video Input
Video Output
Pre-emphasis
Operating voltage
Protection
Current consumption:
VTX2400
VRX2400
Antenna connector
Power connector
Indicators:
Power
Received Signal
Radio
Frequency
Frequency stability
RF Power Output
Local oscillator
Modulation type
Modulation bandwidth
450mA Good signal threshold
250mA
50 TNC Mechanical
2.1mm jack Dimensions
Weight
RED Enclosure Material
GREEN
Environmental
Operating temperature
Storage temperature
1 Vp-p into 75W BNC
1 Vp-p into 75W BNC
CCIR PAL 405-1
10-15 V DC
Reverse Polarity
1394MHz
+/- 40KHz
500mW
PLL Synthesized
FM
4.5MHz
-80dBm
125x62x30mm
240g
Extruded aluminium
-10 to +55°C
-25 to +85°C
Radio Modem
Frequency Range
Channel Spacing
No. of Channels
Transmitter
RF Power Output
Adj. Channel Power
Freq. Tolerance
FM Deviation
Receiver
RF Sensitivity
Intermodulation
SE Version
Height
Width
Depth
Weight
Enclosure
406-470MHz*
Adj. Channel Rejection
-70dB
25KHz RSSI Threshold Level
-105dBm 16k
32
-110dBm at 8k
Max Bit Rate
16kbps
50-500mW (4 steps) Modulation
GMSK
-37dBm Interface Baud Rate
150-19.2 Kbaud
+/- 1KHz Parity
Odd, Even, None
+/- 3.5KHz Power Consumption at 240V
Transmitter at
7.2W
500mW
-110dBm for 10BER
Receiver
4.2W
-70dB
230mm
88mm
80mm
800g
IP67 weatherproof
SED Version
Height
Width
Depth
Weight
Enclosure
280mm
180mm
120mm
2800g
IP67 weatherproof
Radio Data Technology Ltd
10-11 Taber Place Crittall Road Witham Essex CM8 3YP England
Telephone: 0044 (0) 1376 501255 Telefax: 0044 (0) 1376 501312
Email: sales@radiodata.co.uk URL: www.radiodata.co.uk
A member of the CML Microsystems Plc group
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