First published in Electronics World […]
Long-Range, Low-Power Data Links with […]
Article by Mohammed Morsy, Alexandria […]
9th - 12th November 2010, […]
Radiometrix has been manufacturing radio modules for almost 40 years. In that time new designs have improved older ones, and technologies have changed. Some critical parts have even become obsolete. This has produced a family of legacy designs but Radiometrix does not just discontinue products and does not leave users options. Legacy modules can either still be manufactured (with some limitations and caveats) or technical support assistance can be provided to guide users towards more up to date (and often better, and cheaper) equivalents.
Our legacy product range includes the:
TX1, RX1, NRX1, NTX2, NRX2, BiM1 single channel crystal controlled narrowband modules
TX2, RX2, & BiM2 SAW based 433MHz radios. (Both supplanted by modern PLL based designs)
TX2A, RX2A, TX3A, RX3A, BiM2A, BiM3A, BiM2B, HVR2 (all with obsolescent part issues)
BHX2 (458MHz high power, transceiver superseded by SFX2).
Many Radiometrix modules are conventional single frequency radios, transmitting their RF energy in one distinct channel (even multichannel units only use one channel at a time).
The LRM3 is different. It is a transceiver built around the highly innovative Semtech “LoRa” chip-set, which uses a spread-spectrum technique to distribute it's transmitted power over a much wider spectrum. Up to a MHz or more.
This method (in the past limited to high security military radios) gives a LoRa radio exceptional resistance to jamming and interception, and allows it to advantageously use very low data rates to get much longer range (for given transmit power). As an example, 10mW 869MHz LoRa radios can reach out 10km or more.
The LRM3 is an innovative solution for very long range control and low speed data transmission.
The most well known low power wireless bands are in the VHF and UHF (400 and 870MHz) regions, but there is an often overlooked world wide allocation at 27MHz.
Radiometrix manufactures 27MHz versions of some of it's better known types of modules. These include the SIL footprint single channel NRX0 receiver and NTX0 transmitter, and the multichannel LMT0 transmitter and LMR0 receiver. With a suitable antenna, these HF units can easily rival the performance of the higher frequency modules.
The established ranges of Radiometrix products already put a lot of functionality into very small packages, but advances in RF devices in recent years has noticeably raised the game. Using state of the art RF silicon devices, the MTX2 (400MHz band) and MTX3 (869MHz) transmitters take the high performance narrowband multichannel performance of the LMT series and condense it into an uniquely compact 23 x 12.5mm footprint, with no performance trade-offs at all. These modules are ideally suited to integration into hand held “fob” sized products.
In the UK, there is a specific allocation on 458MHz for long range, high reliability wireless links (targeting industrial telemetry, telecommand and machine control tasks). These links are narrowband (only) and are allowed to use up to 500mW TX power (for a practical range of well over 1km)
Radiometrix provides a wide range of 458MHz band capable products, but uniquely matched to this band are the SFX2-458 high power fast switching transmitter and the HMT2-458 500mW transmitter.
Products in this application area such as pendant alarms for the vulnerable, emergency cord alarms for disabled facilities, are allowed to operate on a specific 869.2125-869.2375MHz allocation, and require the highest (EN300-220 category 1 “life critical”) performance.
Radiometrix offers a range of uniquely suited products, including the COR3 and SAR3 receivers and the LMT3B, the SAT3 (SIL footprint) and MTX3 (sub miniature) transmitters.
Using the most up-to-date class of fully integrated radio-on-silicon devices, Radiometrix has recently introduced a range of full feature 400MHz (LNM2H and HNM2) and 869MHz band (LNM3 and HNM3) high power (500mW) RS232 compatible radio modems.
This family covers both the simple PCB mounted module type (LNMx) products and more adaptable board level (HNMx) units which provide connectorised RS232 and USB interfaces.
While the flexibility of a raw baseband interface radio is invaluable, there are occasions where a much simpler-to-use “serial cable replacement” is a better choice. These modules fulfil that requirement.
For the 433MHz band there is a choice of TDL2A (bidirectional), RXL2 (receive) and TXL2 (transmit), while on 869MHz the similar TDL3F and DWA3 (with integral antenna) transceivers are available.
Alternatively, Radiometrix offers a range of add-on modem chips, to turn a raw interface module into a radio modem. This range includes the TDL-compatible i9600, the simple i1200 and the more complex M48.
Most wireless modules are relatively low power (typically 10mW) devices. A few bands permit higher power but there are VHF allocations (especially in the USA) where MUCH more powerful transmitters are permitted:
For the 169MHz (UK / EU) and 154MHz MURS (USA) allocations, the 500mW SHX1 transceiver is the module of choice. It combines the high performance circuitry of the LMT, and LMR1 with a higher power transmit power amplifier, in a modest 67x30mm footprint.
US part 90/ part 95 bands allow up to 2 watts. Here the robust aluminium extrusion cased QPT1 transmitter and QPX1 transceiver can provide impressive long-range performance.
In a uniquely small 33x23mm footprint, Radiometrix offers a range of wideband transceivers, supporting the wideband SIL family for applications where bidirectional communications are desired. Again covering both the 433MHz (BiM2C, BiM2G) and 869 or 914MHz (BiM3C and BiM3G), these modules provide a very small yet high performance radio at an attractively low cost.
Where longer range is needed the 500mW BiM3H is the transceiver-equivalent to the TX3FH transmitter.