Radiometrix Ltd, TXM Data Sheet

page 7

A. Helical antenna

B. Loop antenna

RF

C1

C2

C4

C3

RF-GND

C. Whip antenna

16.4cm

RF

0.5 mm enameled copper wire

close wound on 3.2 mm diameter former

433 MHz = 24 turns

Feed point 15% to 25% of total loop length

track width = 1mm

4 to 10 cm inside area

wire, rod, PCB-track or a combination

of these three

433 MHz = 16.4 cm total from RF pin.

2

RF

Duty Cycle requirements

The duty cycle is defined as the ratio, expressed as a percentage, of the maximum transmitter “on” time

on one or more carrier frequencies, relative to a one hour period. Where an acknowledgement message

is required, the additional transmitter “on” time shall be included.

There is a 10% duty cycle restriction on 433.050-434.790 MHz band in most of the EU member states.

The TXM-433 is a RF module intended to be incorporated into a wide variety of applications and

finished products, Radiometrix has no control over the end use of the TXM-433.The harmonised band

433.050 to 434.790 MHz as detailed in Annex 1 Band E of CEPT/ERC Recommendation 70-03 (which

can be downloaded at http://www.ero.dk/scripts/docmanag98/dm.dll/QueryDoc?Cat=Recommendation)

has list of countries where Duty Cycle restriction apply.

Module users should, therefore, ensure that they comply with the stated Duty Cycle requirements of

the version of CEPT/ERC Recommendation 70-03 in place at the time of incorporation of the TXM-433

into their product. It should be noted that the stated Duty Cycle must not be exceeded otherwise any

approval granted for the TXM-433 will be invalidated.

figure 6: Antenna configurations