Full Control
The LCU has a switchable balanced preamplifier with a gain of nominally 18 dB, optimally placed at the antenna to maximise signal to noise ratio and swamp any external noise pickup on the feeder. Ahead of the preamp are three selectable 7-pole filters, two low-pass and one high-pass, to give your receiver (and our preamp) an easier life if needed. The high-pass filter and one low-pass filter overlap to produce a band-pass response as a fourth filter option.
The terminating resistor in K9 mode is adjustable in 50 Ω increments from 250 Ω to 950 Ω.
The CIU (Common Interface Unit) has a 5-position attenuator: 0 dB, -6 dB, -12 dB, -18 dB and infinity (which isolates the receiver, terminating it in 50 Ω).
The combination of LCU preamp and CIU attenuator gives around 36 dB of level control allowing the user to achieve the best balance of signal to noise ratio versus dynamic range.
The CIU also has two auxiliary I/O lines that can be separately configured as inputs, or outputs. These can be operated remotely as well as locally. Uses include additional antenna switching, controlling other equipment, or in a remote scenario, mains-fail indication, intruder alarm, temperature alarm, remote fan control, equipment re-boot etc.
Mute Facility
An auxiliary I/O channel can be set up as a PTT sense line to quickly isolate a connected receiver and protect the LCU preamp from high RF levels. The second channel can be configured as another PTT input or a PTT-out line with a selectable delay. There is also a mute (talk) timer with visual display within the app.