SIELCO srl
- Via Toscana, 57/59 - 20090 BUCCINASCO (Mi) - ITALY - tel. 02 - 45713300 - www.sielco.org
EXC/RTX19 - USER & MAINTENANCE MANUAL - rev.1.5 - 05/16
Page 5
GENERAL DESCRIPTION
The EXC19 transmitter and its companion RTX19 receiver are the core of a high quality,
synthesised studio-to-transmitter link (stl), to be used for broadcast repeaters in conjunction with
any standard FM or AM transmitter. Design of this apparatus derives from the extablished EXC/
RTX18 series stl whose main circuitry is still extensively used here with new controllers and more
advanced oscillators in a modern and attractive "slim" case.
They allow the reception of mono or stereo signal and its retransmission without using any
additional stereo-coder on the receiving end: in both cases the LF output signal from the receiver
must be sent to the stereo input (linear or not pre-emphasised) of the local FM rebroadcast
transmitter.
The stl is built for several different frequency slots in the SHF range. While the exterior
cabinet, the controls, the basic circuitry and the performances are the same, some internal
components vary as required to cover this wide frequency band. Usually these components are
the local oscillator, the power amplifier and the input/output filters
In the whole SHF range the internal modules are the same, with some tuning adjustments.
The factory adjusted frequency slots are 10 to 50 MHz wide and must be specified in the order.
In the preset sub-range, the frequency and power of the transmitter may be freely changed on
the field. The receiver on the contrary requires some more adjustment for wider frequency
displacement: in fact the adoption of a very narrow, low loss microwave input filter permitted
to achieve the best possible rejection of interfering signals in the band at the expense of some
frequency agility. So nearly 8-10MHz may be used without any retouching but wider variation
up to 50-60MHz will require retuning of the input filter.
Being the apparatuses completely digitally controlled, they are extensively on field program-
mable by front panel or remotely in every respect. The alphanumeric display permits easy and
accurate metering, adjustment and continuous monitoring of modulation levels, power, operation
and internal parameters. All these information are externally available on the same RS232 I/O port
that may be used to remotely control the transmitter. In addition to the serial I/O, some signals and
controls are available on a parallel I/O socket for easy interfacing with others analog controllers
or supervisory systems. A powerful 3-levels password management permits a very high degree
of security and privacy as may be required in different situations.
The LF input and output levels are precisely adjustable over a broad range, by means of
0.5dB stepwise variable attenuators. The transmitter has also an auxiliary input, specifically
designed for RDS and SCA encoders. A modulation monitor output permits to control other
transmitters or STL's with the same internally processed high-quality mpx signal. Furthermore,
the system is optimised to be compatible with external digital companding encoder/decoders
and to provide RDS and SCA signals, with almost no attenuation.
Optional top-quality stereo encoder/decoder boards may be factory installed on the transmitter/
receiver or field retrofitted with minimum required technical skill. The powerful internal software
and monitoring functions recognise their presence and enable the functions. A universal switch-
mode power supply permits operation in the extended 95-250 Vac range with no intervention and
a 24 V back-up battery input is provided too.