User Manual

STTRS DOCUMENTATION
Document Number 80-330501HBKM – Issue A - Draft Page 406 of 500
21.3.2.12. Dummy Load (80-007401)
When a combiner system is used to split or combine RF signals, in many cases it is most cost
effective to use a standard stock item 4, 6 or 8 port device where, in fact, only a 3 or 6 port device is
needed. In this case the Four Way Splitters (05-003302) each have their unused ports terminated with
Dummy Load (80-007401) in order to preserve the correct impedance of the devices over the
specified frequency range. This also has the advantage of allowing future expansion capability should
extra channels or other functions become necessary.
Dummy Load (80-007401) Specification
Parameter Specification
Frequency Range 0 to 1000MHz
Power Rating 1.6 Watts
0-500MHz 1.2:1 VSWR
(Max)
500-1000MHz 1.3:1
Temperature -20 to +55°C
Connector ‘N’ type Male
Nominal Impedance 50 Ohms
21.3.2.13. 12V (Single) Relay Board (80-008901)
The General Purpose Relay Board allows the inversion of signals and the isolation of circuits. It is
equipped with a single dual pole change-over relay RL1, with completely isolated wiring, accessed
via a 15 way in-line connector. The relay is provided with polarity protection diodes and diodes for
suppressing the transients caused by "flywheel effect" which can destroy switching transistors or
induce spikes on neighbouring circuits. It’s common use is to amalgamate all the alarm signals into
one, volts-free relay contact pair for the main alarm system.
80-008901 Specification
PARAMETER SPECIFICATION
Operating voltage 8 to 30V (floating earth)
Alarm threshold Vcc - 1.20 volt +15%
Alarm output relay contacts
Max. switch current 1.0Amp
Max. switch volts 120Vdc/60VA
Max. switch power 24W/60VA
Min. switch load 10.0µA/10.0mV
Relay isolation 1.5kV
Mechanical life >2x10
7
operations
Relay approval BT type 56
Connector details Screw terminals
operational -10°C to +60°C Temperature
range
storage -20°C to +70°C
21.3.2.14. Dual Diode Assembly (94-100004)
The purpose of these dual diode assemblies is to allow two DC voltage sources to be combined, so
that the main DC rail within the equipment can be sourced from either a mains driven PSU, or
externally through an XLR connector or from dual mains driven PSUs. They are very heavy-duty
diodes and they prevent any reverse current from flowing back to their source or the alternative
supply rail. Combining diodes such as these will also be used if the equipment is to be powered from
external back-up batteries.