Narrowband SIL and BiM radios

A guide to the (UHF) NRX2B, NTX2B, NiM2B, NiM2F, and (VHF) NRX1B, NTX1C, NiM1B and NiM1F

SIL and BiM pin-outs and packages, but true NARROWBAND performance

This large family of common footprint and function modules from Radiometrix represent a higher performance narrowband alternative to the existing wideband SIL and BiM modules.
Consisting of receiver, transmitter and transceiver modules covering an exceptional range of operating frequencies, this family provides superior RF parameters for trouble free operation in hostile RF environments, where a simpler module might not be adequate.

Key features

Narrow Band (for where existing wideband modules lack the necessary range or robustness)
User programmable single frequency operation (No “custom channel frequency” quartz)
Excellent RF performance.
Matching family footprints, pin-outs and interfaces
Highly resistant to mechanical vibration. Very low microphony
Can be ordered on a wide range of frequencies in VHF and UHF bands. Re-programmable via serial link.
Conform to EN 300 220-2 (significantly better than category two) and EN 301 489-3
Evaluation Boards available


The NiM1B (VHF) and NiM2B (400MHz UHF) modules provide genuine narrowband transceiver functionality with the same DIL 33x23mm package, footprint and pin-out as the BiM2A/C/G types.
Receiver-only and transmitter-only versions of these transceivers can be offered, in instances where the customer may prefer the BiM format over SIL packages

Receivers and transmitters

The SIL package members of this family are the NRX1B (VHF) and NRX2B (400MHz UHF) receivers, and the NTX1C (VHF) and NTX2C (UHF) transmitters. All these modules are highly capable programmable frequency designs (using low phase noise sigma delta PLL frequency sources, locked to a high stability TCXO reference) combined with (in the RX paths) high rejection crystal and ceramic channel filters.

TX: Single TX modulation input (usable for digital data or AF)
Transmit output power up to 25mW (+14dBm)
(up to 100mW (+20dBm) for NiM1F and NiM2F)
Low power (< 20mA at 3v typical for 10mW RF output)

RX: Raw audio and squared (digital logic) baseband outputs
Dual gate mosfet (UHF) or JFET (VHF) mixers for exemplary large signal RX performance
Wide dynamic range analogue RSSI output

All: Easily used enable pins (separate TX and RX enable pins. Negligible shut-down current)
Simple frequency re-programming via a serial data connection
Data rates up to 10kbit/sec

And more
In addition to the standard “B” suffix members of this family, Radiometrix have recently released the NTX2D and NRX2D transmitter/receiver pair. These units employ a different (and more advanced) RF PLL device to provide much faster power-up from cold (<5mS compared to 20mS or more for a “B” series unit) and lower TX current consumption


These radios are intended for more challenging applications, where the economy and small size of the wideband families is still needed, but higher radio link performance, and longer “range per milliwatt” is desired.
As narrowband radios, they can also be used on a wider range of “narrowband only” allocations (such as most VHF sub-bands, and the industrial 458MHz band in the UK). This gives a much wider range of less congested options, better suited to higher reliability, higher integrity industrial control and telemonitoring applications.
For industrial applications where significant levels of mechanical vibration are encountered, these modules share the high vibration resistance (low microphony) of their wideband equivalents

Beyond the basic family

These modules (being standard 25KHz channel spacing narrowband radios) can be used in conjunction with any other Radiometrix narrowband types operating on the same channel frequency (for example: the LM series, MTX and HMT transmitters, SMX, USX and SHX transceivers, and all the high performance TR2M (etc) family units).

While these simpler units do not incorporate the 1200 baud modem functionality of the larger multichannel types, compatible operation can be easily provided by adding an i1200 modem chip to the baseband interface.

Evaluation & Application Boards

To further simplify the implementation of user designs, a number of application/demo boards are offered, with all necessary connectors and support and interface circuitry.
The feature-rich NBEK test board is ideally suited to these modules (with appropriate SIL or BiM footprint carrier boards fitted) while the older UNI-EVAL demonstration board also has SIL and BiM package connectors.
The full range of Radiometix's control and modem chips (M48, CTA88, Smallcontroller and i1200 to name a few) can be used with this highly adaptable family of modules.