UHF High Power Transmitter

The TX2H is a 433.92MHz FM transmitter module with a power output of 25mW nominal. It is a 100% pin-compatible drop-in replacement for the Radiometrix TX2 and can be used to replace the TX2 in applications where greater radiated power is desired (for example when space limitations dictate the use of small and inefficient antennas, or in countries where the extra power is permitted). The TX2H transmitter can be used with RX2, RX2A andf RX2G receivers.

Figure 1: TX2H-433-64

Instead of the SAW-based technology of the TX2, the TX2H uses a PLL circuit locked to a crystal for better frequency stability over a wider temperature range (-40C to +85C), at the expense of slightly slower power-up.
The module can be made available if required in an extra-high-power version (TX2EH), in the same footprint and pinout but giving 100mW nominal output power at 5V supply with a current consumption of less than 45mA (DC to RF conversion efficiency better than 45%).


  • Standard frequencies: 433.92MHz and 434.42MHz
  • Hi power drop in replacement for TX2
  • Data rates up to 64kbps
  • Usable range over 500m
  • Fully screened
  • Low power requirements
  • Conforms to European EN 301 489-3 and ETSI EN 300 220-3 (for ERP @ 10mW)
  • Conforms to Australian/New Zealand AS/NZS 4268:2003


  • Handheld terminals
  • Data loggers
  • Industrial telemetry and telecommand
  • In-building environmental monitoring and control
  • High-end security and fire alarms
  • Vehicle data up/download

Technical Summary

  • Operating frequency: 433.92MHz and 434.42MHz
  • Supply : 3V or 5V regulated
  • Current consumption: 23mA typical
  • Transmit power: +14dBm (25mW)
  • Data bit rate: 64kbps max
  • Size: 32 x 12 x 5.5mm

Evaluation Platform: Universal Evaluation kit or Narrow Band Evaluation Kit
Matching receiver: RX2A-433-10 / RX2A-433-64 or RX2G-433-15 / RX2G-433-64

Figure 2: TX2H block diagram

Figure 3: TX2H Footprint (Top of the unit) view

Pin Description - TX2H

1 RF GND RF ground, internally connected to the module screen and pin 4 (0V). This pin should be directly connected to the RF return path - e.g. coax braid, main PCB ground plane etc.
2 RF OUT 50Ω RΩoutput to antenna. Internally DC-isolated.
3 Vcc +ve supply pin. The module will generate RF when the Vcc supply is present. Max ripple content 0.1Vp-p. A 100nF de-coupling ceramic capacitor is suggested.
4 0V DC supply ground. Internally connected to pin 1 and module screen.
5 TXD This DC coupled modulation input will accept either serial digital data ( 0 V to Vcc levels) or high level linear signals. Input impedance is 100 kΩ

Preliminary Specifications (TX2H-433-64-5V)

Figures apply at +25°C, 5.0V supply unless otherwise stated.

Operating temperature range -40°C to +85°C
Supply voltage 4.5 - 5.5V (5.0V nominal, 6.0V absolute max.)
Supply current 23mA typical
Output power +14dBm (25mW), ±1dB
DC to RF conversion efficiency 22% approx.
Harmonics/spurious emissions <-40dBm
Initial centre frequency accuracy ±15kHz max.
Centre frequency variation over volts/temp ±40kHz max.
FM deviation ±30kHz typical
Power-up time (DC on to full RF output) 1.1ms typical, 1.5ms max.
Baseband bandwidth DC-35kHz approx.
Maximum raw data rate 64kb/s
Required TXD input levels 0V (logic 0), +5V (logic 1). Non-inverting.

Limitation of liability

The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd reserves the right to make changes or improvements in the design, specification or manufacture of its subassembly products without notice. Radiometrix Ltd does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. This data sheet neither states nor implies warranty of any kind, including fitness for any particular application. These radio devices may be subject to radio interference and may not function as intended if interference is present. We do NOT recommend their use for life critical applications.
The Intrastat commodity code for all our modules is: 8542 6000.

R&TTE Directive

After 7 April 2001 the manufacturer can only place finished product on the market under the provisions of the R&TTE Directive. Equipment within the scope of the R&TTE Directive may demonstrate compliance to the essential requirements specified in Article 3 of the Directive, as appropriate to the particular equipment.
Further details are available on The Office of Communications (Ofcom) web site:
Licensing policy manual