Multi Channel Transmitter (MCTX) - Installation,
Commissioning and Maintenance
Page 8 of 16
Overloaded UHF output
Typical UHF output
are only approximate and will be affected by adjacent objects reflecting and absorbing the
signals.
Warning
: Do not connect your spectrum analyser directly to the output of the transmitter as the
high signal level could permanently damage the mixer diode in the analyser.
Over modulation of the upconverter will produce noise and high intermod and this situation must
be avoided to maintain compliance with the appropriate standards. When viewed on the spectrum
analyser the radiated signal will be shown with high levels of noise as shown in the captured
display.
If your spectrum analyser has the facility to save the results do so, as this will show that you have
exercised due diligence when setting up the system.
It is the responsibility of the installer to ensure that the installed system fully complies with all
the technical requirements of the R&TTE directive.
Connecting the audio signals
The audio input signals should be connected to the two phono sockets for each channel using a
suitable screened lead. A nominal signal level of -10 dBu is required for full modulation of the
VCO.
The alarm input is designed to operate from a normally open volt free contact in the fire alarm
control panel. The wires should be connected between pins 2 and 3 of the XLR connector. Pin
one is for the shield of a screened cable. We recommend a balanced pair screened cable is used
for the connection to reduce the effect of any unwanted signals or interference.