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CM 7283 VHF-UHF single input
MATV Distribution Amplifiers
Introduction and Applications
CM 7283
Digital applications
Using a UHF pre-amplifier
Installation Instructions
This is single input wideband amplifier covering Bands to 40-862MHz, VHF and UHF with
its own gain control should be used where the signals from VHF and UHF antennas have
been combined before reaching the amplifier.
These fully screened amplifiers are ideal for handling TV and FM DAB radio signals in
small and medium sized MATV distribution systems. These amplifiers have a single
output and are used in conjunction with a passive distribution network built using
splitters and taps (also available from Labgear). Advice on required.
Both units are suitable for handling digital terrestrial TV(DTT) signals in addition to the
analogue services.Distribution of DTT signals requires careful attention to system design
and to signal levels for satisfactory results.
In weak UHF signal areas, or where a long downlead cable run is required, it may be
desirable to use a masthead preamplifier mounted close to the UHF antenna. These MATV
amplifiers feature built-in12V input line-powering; there is no need to use a separate
power unit for the masthead amplifier.
The built-in line-power is rated at 40mA (fully short-circuit proof) and is compatible with the
majority of Labgear masthead preamplifiers.
The preamplifier gain used should be kept to a minimum and generally only needs to
exceed the down lead cable loss by about 6dB. A single-stage15dB gain masthead
(PUM111) will be suitable for the great majority of applications. Use of excessive amounts
of gain will lead to severe cross-modulation and intermodulation problems.
Waste electrical and electronic products must not be disposed of with household waste.
Please recycle where facilities exist.
Check with your Local Authority or Retailer for recycling advice.
Labgear
Kingfisher Wharf
London road
Bedford MK42 0NX
Tel: 01234 263737
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Installation
Location
Fixing
Electricity supply
Signal connections
Monitor point
Each amplifier is provided with a -30 dB monitor point to allow the outgoing signal quality to be
checked using a spectrum analyser. Since the monitor point is of the resistive (non-directional) it is
not very accurate, for making accurate measurements of signal launch levels install a FHU301 Tap on
the main output.
Input and output signal connections are made us ing Type-F (IEC 60169-24) connectors. CAI Benched
marked cable to EN 50117-2 should be used, in conjunction with high quality crimp F connectors. The
F connectors should always be tightened with a spanner; leaving them finger tight may result in
unwanted signal ingress or leakage, as well as suck-outs in the frequency response.
These amplifiers are not intended for domestic use and are supplied without a mains plug fitted. The
electrical supply arrangements to the unit should be in accordance with BS 7671 ('IEE Wiring
Regulations'). Additional information is given in the GENERAL SAFETY PRECAUTIONS panel on page 4.
The amplifier may be connected to the mains using either a switched fused
connection unit, or a plug
and socket connection. The fused connection unit method reduces the risk of accidental disconnection
and is recommended.
If the amplifier is not connected using a fused plug or connection unit it must be protected at the final
distribution board by a fuse or MCB of rating not exceeding 6A. An isolating switch should be provided
near to the unit to allow it to be disconnected from the supply when necessary.
The recommended clearances and other precautions given in the installation section of
these instructions must be observed to prevent overheating. In addition, the units should
not be fixed where they are likely to become smothered by curtains or other fabrics, etc.,
or by thermal insulation materials in a roof space or similar building void. The units should
not be left resting on a carpet.
Recommendations for the method of connection are given in the instructions section of
these instructions. If the fused connection unit or plug to be used is supplied with wiring
instructions such
as cable stripping details, these should be followed. The brown wire of
the supply cord must be connected to the live (L) terminal of the connection unit or plug
and the blue wire to the neutral (N) terminal.
Neither wire should be connected to the earth (E) terminal of a connection unit or 3-pin
plug. Ensure that the cord grip in the connection unit or plug is correctly used and clamps
the sheath of the cord firmly.
Fuse type and rating: where the supply connection is made using either a fused
connection unit to 1363-4 or a plug to BS 1362-1, a 3A (three ampere) BS fuse to BS1362
should be fitted in the wiring accessory. Original and replacement fuses should carry the
ASTA or BSI approval mark.
The amplifier should be fixed to a wall or other suitable hard surface, using suitable screws and
masonry plugs (not supplied). The amplifier should not be left supported only by its wiring, nor
should it be left resting on a carpet or other insulating and/or inflammable surface.
Important note:
attention is drawn to the GENERAL SAFETY PRECAUTIONS panel on page 4 which
con
tains advice relating to the safe installation and operation of these products.
Choose a location for the amplifier from which it is convenient to run the antenna and outgoing
system trunk cables. Typical examples of suitable locations are a roof space or cupboard. In weak signal
areas it is helpful to keep the antenna cables as short as practicable. Select a cool, dry location to
install the amplifier. This means a location Where the ambient temperature will remain between -10°C
and +40°C, and which is free from risk of dripping or splashing water, etc. The fixing location should
allow adequate access to the equipment for wiring and maintenance. Clearance of at least 25mm
should be allowed around the top and left- hand side of the unit for ventilation. More clearance will be
needed under and to the right of the amplifier to allow access for cables.
Specifications CM7283 Units
Bandwidth 40-862 MHz
Gain 32 dB
Gain Flatness
±
2
dB
Gain Control 20 dB
Noise Figure 4.5 dB
Output Capability
111
dB
µ
V 4ch.
110
dB
µ
V 5ch.
107
dB
µ
V 8ch.
104
dB
µ
V 16ch.
Return Loss 12 dB input
14 dB output
Line power +12 V (voltage)
40 MA (load)
Input configuration Single
Monitor point -30
Connectors f-type IEC16069-24
Mains supply 230 V 50Hz
Supply load 5.5W
°
C
Operating temp. 0-40
Safety standard EN 60065
Size (h) x (W) x (d) 45 x 100 x 163 mm
Weight 525
g
General Safety Precautions
TO PREVENT OVERHEATING
These appliances are not waterproof. They are for indoor use only and must not be fixed
where they could be exposed to dripping or splashing water. Objects containing liquids
should not be placed on or near the appliance.
To prevent risk of fire, no object with a naked flame should be placed on or near the
appliances or the wiring to them.
OTHER PRECAUTIONS
CONNECTION TO THE MAINS SUPPLY
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