Narrowband transceivers boast longer ranges

The new SMX series transceivers from Radiometrix are compact (53 x 32 x 12mm) multichannel narrowband radios intended for a wide range of industrial wireless datalink applications.

The new SMX series transceivers from Radiometrix are compact (53 x 32 x 12mm) multichannel narrowband radios intended for a wide range of industrial wireless datalink applications.

This family of designs comprises VHF (SMX1: 173MHz band) and UHF (SMX2: 433MHz band) units with identical footprint and pinout.

Key features of both units include: high performance double conversion superhet receiver sections (-120dBm/12dB SINAD sensitivity, -60dB RX spurii, -85dB blocking), and a 128 channel (maximum) PLL based local oscillator system.

The user interface provides RSSI, AF and and data outputs.

A 3bit (1 of 8) parallel frequency select port is provided, but the units can also be fully reprogrammed via the RS232 interface pin.

Both radios support datarates of up to 5Kbit/s (or a DC-3kHz AF passband), in a 25kHz RF channel.

If a simpler interface is needed, then a 1200 baud transparent half-duplex mode can be selected, releasing the user from the need to provide control signals to key the transmitter or expend processing power formatting and decoding the datastream.

In this mode the task of bit-coding, buffering, framing and timing is automatically handled by the internal processor.

Power requirements are 4.2-16V at between 20mA (receive) and 40-65mA (transmit, depending on power output).

These radios are supplied in a fully screened enclosure and conform to ETSI EN300 220-3 and EN301 489-3.

The SMX1 operates on the 173.200-173.325MHz (UK) band, or can be ordered on specified customer frequencies (any 1MHz band between 130 and 180MHz).

Transmit power as standard is 10mW (giving a range of well over 1km), but can be supplied between 1-50mW if required.

The SMX2 is designed for the 433.05-434.79MHz European ISM band, but can also be ordered on the UK 458MHz and Asian 419MHz bands (and other frequencies, subject to availability of the necessary receiver front end SAW filters).

The SMX2 is a 10mW output power device.

Applications for Radiometrix's SMX transceivers are many, but these units are particularly suited to applications where (compared with simple wideband radios) greater range, number of channels and resistance to interference are needed, such as: data loggers; heavy machine remote controls; industrial telemetry and telecommand; high-end security and fire alarms; and large-building environmental monitoring and control.

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