Multi Channel Transmitter (MCTX) - Installation,
Commissioning and Maintenance
Page 6 of 16
Location of the aerial and the up converter
The performance of the radio system is very dependant on the location of the aerial and up
converter, a poorly sited aerial will seriously degrade the performance of the system. The signals
travel in a straight line from aerial to receiver and will be attenuated by any object in the signal
path. Choose a location which is above any object which is likely to restrict reception of the radio
signal, placing it well above head height will reduce the effect of people who are in the way. Try
not to have any metal objects such as steel cupboards, shelf brackets, TV sets or electric wires
near to the aerial which will cause reflections.
The up converter should be sited close to the aerial so that the 1 metre feeder cable can be
connected to both the up converter and the aerial without any sharp bends or kinks in the cable
which will cause reflections to the RF signal and create standing waves so reducing the output
signal from the aerial. At a frequency of 864 MHz the loss in the feeder cable is 1 dB per metre.
The aerial will need to be connected to the aerial socket located on the end of the up converter
using the BNC feeder cable supplied. Do not be tempted to cut the length of, or replace the feeder
cable as this is tuned in the factory for the best output signal. Changing the cable or altering its
length will seriously degrade the performance of the system and may cause it to fail to meet the
required standards. Select the best location in the room and position the aerial so that it is
mounted vertically (with the Audeon text reading the correct way round) to provide the strongest
signal. The range which you can expect is up to 100 metres but this is dependant on other factors
such as walls, metal objects, other equipment and people, all of which will attenuate the signal.
Radio Frequency Connections
The baseband processor should be installed in a standard 19" rack enclosure. There are two BNC
sockets on the rear panel which will require to be connected to the up converter using RG 58 (or
similar - see appendix I) coax cable. The two connectors are colour coded red and black.
FM - BLACK is the VHF modulating signal output from the processor which is
fed to the up converter.
FC - RED has the +15v dc supply for the up converter.
It is good practice to mark the cables at both ends with red and black tape for future reference.