General Instructions for both Mode 1 & 2
Signal Connections
To preserve RF screening integrity, the signal connections to the amplifier should be made using
good quality coaxial cable and connectors. This is particularly important with DTT to minimise the
ingress of impulsive electrical interference. The use of cable benchmarked under the CAI scheme
is recommended.
Crimp F connectors, used in accordance with the manufacturer
’
s instructions, will give the best
results. The importance of achieving the sound braid connections cannot be over
-
stressed.
Connectors should be tightened with a spanner, not left finger
-
tight. Unused inputs and outputs of
this amplifier do not need to be terminated.
Power Supplies
•
PROPSU112X
-
12V power unit connected anywhere in the UHF return feed (i.e. in the line
between RF OUT
-
2 of the Sky receiver and the amplifier
’
s UHF input) Fig.2(a);
•
PROPSA125
-
a local AC/DC mains power adaptor connected to
the DC power port, as in Fig.2
(b). The adaptor doesn't need to be regulated but does needs to have a standard 2.1mm DC
connector with the correct polarity (centre pin +ve). If a 3rd party adaptor is to be used its
output should conform to the requirements given in the technical data section (page 8).
When using this option the UHF input must be directly connected to the Sky receiver RF
OUT
-
2, since the 9V second outlet power needs to be sensed at the UHF input to switch the
amplifier to Mode 2. The current drawn from the Sky receiver in this configuration is very
small (typically 3
-
5
mA).
Mains Power Supply
Any fixed wiring installed to supply power for this amplifier should comply with BS7671 (IEE wiring
regulations) and, where relevant, Part P of the building regulations. Refer to the instructions
provided with the power supply unit for other safety information.
Splitting outputs
As with any multi
-
way amplifier the output signals can be split as illustrated in Fig1(b) to provide
additional outlet points. The
PRO
ception PROSPL204 splitter is suitable for this in Mode 1 and
introduces approximately 4dB insertion loss. Splitting outputs in Mode 2 is not recommended,
since it is not possible to provide individually protected eye power to the split outputs.
Signal levels
This amplifier has relatively low forward gain figures and assumes that adequate input signal levels
will be available from properly installed aerials. The amplifier gains are sufficient to compensate
for additional distribution cable losses in a typical domestic
-
scale systems whilst avoiding the
intermodulation and other overload problems which result from the use of excessive gain.
Recommended minimum and maximum signal levels for each of the frequency bands are given in
the Technical data section on page 8. Particular attention should be paid to the input VHF radio
signal levels. In city areas, very strong signals are often received and it may be necessary to use
attenuators on one or both of the VHF inputs to avoid overloading the amplifier.
Outlet plates
The use of outlet plates is recommended to provide a professional standard of finish to the
distribution system.
PRO
ception
’
s screened outlet plates are recommended for use with this
amplifier. The diplexed TV and radio plate (PROOUT12C) allows both TV and radio equipment to
be connected simultaneously to an outlet point. Single outlets (PROOUT11C) may also used and
will allow either TV or radio equipment to be used. The system diagrams in Fig.1&2 show both
types of plate in use.
In Mode 2, a PROOUT11C plate may also be used to provide the UHF return input connection from
the Sky receiver, as illustrated in the diagrams in Fig.2.
Installation location and fixing
Choose a location for the amplifier which is dry and not subject to prolonged ambient temperature
conditions of less than
-
10°C of more than +40°C. Fix the unit to a sound vertical surface such as a wall
or equipment mounting board. Ventilation gaps of at least 50mm should be left around the front and
all sides of the unit. More clearance will be required around sides where cables are connected.
Do not install the amplifier or its associated power unit where they may become smothered with
curtains or other soft furnishing fabrics. When installing the amplifier and power unit in a roof space,
ensure that they will not come into contact with thermal insulation material.
System Equipotential Bonding
A bonding terminal is provided on the amplifier for use where necessary. Distribution systems
supplying signals to more than one household should comply with he safety requirements of BS EN
60728
-
11. This effectively requires earthed equipotential bonding of the system. The use of isolated
outlet plates is no longer recommended since they compromise screening integrity and allow ingress of
interference.
Advanced Configuration Features
Note: access to the features described in this section involves opening the unit. The procedures below should only be carried out by a
competent person, preferably under workshop conditions.
•
UHF input line
-
power (preamplifier power):
where equipment (such as an attenuator) connected
to the UHF input might be damaged by the presence of the 5V output, or may cause the 30mA
current rating to be exceeded, the input line
-
power can be permanently disabled by removing the
internal LINE
-
POWER jumper.
•
Forced Mode 2 operation:
where Mode 2 operation is desire, but it is impracticable to connect a
Sky receiver directly to the UHF input to provide a 9V sense voltage. The unit can be forced into
Mode 2 by placing a jumper link on the 2
-
pin header labelled FORCE MODE 2. Since UHF input line
-
power will not usually be required in Mode 2, the existing LINE
-
POWER jumper can simply be
moved to the FORCE MODE 2 header position. Forced Mode 2 operation is only relevant when a
local power unit is in use, connected to the DC power port.
•
Access:
to open the unit remove the four corner screws from the rear cover. Separate the two
halves of the moulded cover and withdraw the screened amplifier assembly, together with the
attached DC port connector. Remove the top metal lid (this is the side with the LED). One side of
the PCB is now exposed. Take great care not to disturb any of the coils, as this could de
-
tune the
input filters. The LINE
-
POWER jumper is located just above the LED; the Force MODE 2 jumper is
in the bottom right
-
hand corner of the board, near the equipotential bonding terminal.
•
Re
-
assembly:
when reassembling the unit, take care to ensure that the LED does not become
trapped and pushed inside the unit, and that the DC port connector is correctly seated in the
cover mouldings before replacing the screws.
Set
-
Up
The Sky receiver should be configured in its INSTALLER SET
-
UP menu to provide power on RF OUT
-
2.
On the Sky handset press SERVICES, 4, 0, 1, SELECT, then select the SECOND OUTLET POWER SUPPLY
option. Set this to be ON (the default state is OFF), SAVE SETTINGS and BACK UP out of the menu.
Interlock function: if a connector is present in the amplifier's local DC power port then power will not
be accepted via the UHF input, regardless of whether the AC/DC mains power adaptor is actually
providing power. This is an interlock function which prevents the Sky receiver trying to power the
entire distribution system in the event of failure of, or loss or power to, the local power adaptor.
Important note: this amplifier is not suitable for powering directly from a Sky receiver. The
configuration where the Sky receiver's RF
OUT
-
2 is directly connected to the amplifier's UHF input
without a local mains power adaptor present is not permitted.
