User's Manual

800MHz Tetra Repeater
User Handbook
Handbook Nō.-55-151501HBK Issue No:-A
Date:-22/04/2005
Page:-
23 of 31
For small signals, below AGC onset, the output control line will be close to 12V and the
AGC attenuator will have minimum attenuation. As the signal level increases the control line
voltage will fall, increasing the attenuator value and keeping the system output level at a
constant value.
The AGC onset level is adjusted by the choice of sampler resistor R1 and by the setting of
potentiometer VR1, (factory set @ time of system test) do not adjust unless able to monitor
subsequent RF levels.
The attenuator comprises a 50Ω P.I.N diode, voltage-variable attenuator with a range of 3 to
30dB. The attenuation is controlled by a DC voltage which is derived from the associated
AGC detector unit.
4.6.2 Technical Specification
PARAMETER SPECIFICATION
Frequency Range: up to 1000MHz
Attenuation Range: 3 to 30dB
Attenuation Steps: continuously variable
VSWR: better than 1.2:1
RF Connectors: SMA female
attenuator: 1W
Power Handling:
detector/amp: >30W (or as required)
operation: -10°C to +60°C
Temperature Range:
storage: -20°C to +70°C
attenuator pcb 50 x 42 x 21mm
Size:
detector/amp pcb 54 x 42 x 21mm
attenuator: 90gm
Weight:
detector/amp: 100gm
4.7
12V Single Relay Board (80-008901)
4.7.1 Description
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.
Note that the board is available for different voltages (12 or 24V) depending on the type
of relay fitted at RL1.