ER400RS EASY RADIO, ER400RS Datasheet - Page 14

• Manufacturer Part Number: ER400RS
• Description: MODULE, RX, FM, 433MHZ
• Manufacturer: EASY RADIO

Specifications of ER400RS

• External Depth: 4mm
• External Length / Height: 14mm
• External Width: 37mm
• Frequency: 433MHz
• Operating Temperature Max: 65°C
• Operating Temperature Min: -20°C
• Rf Sensitivity: -105dBm
• Range: 250m

PCB Layout
The Ground (0 Volt) pins of the receiver should be connected to a substantial ground plane (large area of
PCB copper) connected to 0 Volt. It is suggested that a double sided PCB be used with one layer being the
ground plane.
Power Supply
The supply used to power the receiver should be ‘clean’ and free from ripple and noise (<20mV p-p total). It
is suggested that 100nF ceramic capacitors be used to de-couple the supply close to the power pins of the
receiver. The use of ‘switch mode’ power supplies should be avoided as they can generate both conducted
and radiated high frequency noise that can be very difficult to eliminate. This noise may considerably reduce
the performance of any radio device that is connected or adjacent to the supply.
Antennas
The receiver can be used with the various common types of antenna that match the 50 Ohm RF Input/Output
such as a monopole (whip), helical or PCB/Wire loop antennas.
Monopole antennas are resonant with a length corresponding to one quarter of the electrical wavelength
( /4). They are very easy to implement and can simply be a ‘piece of wire’ or PCB track which at 434MHz
should be 16.4 cms in length. This should be straight, in ‘free space’ (kept well away from all other circuitry)
and should be connected directly to the Antenna pin of the receiver. If the antenna is remote it should be
connected via a 50 Ohm coaxial feeder cable or transmission line. A 50 Ohm transmission line can be
constructed on FR4 board material by using a 3mm wide PCB track over a ground plane. This should be
kept as short as possible.
Helical antennas are also resonant and generally chosen for their more compact dimensions. They are more
difficult to optimise than monopole antennas and are critical with regard to surrounding objects that can
easily ‘de-tune’ them. They operate most efficiently when there is a substantial ground plane for them to
radiate against.
Wire or PCB Loop antennas are the most compact antennas but are less effective than the other types. They
are also more difficult to design and must be carefully ‘tuned’ for best performance.
The Internet can provide much useful information on the design of Short Range Device (SRD) Antennas.
LPRS Data Sheet
Easy -Radio ER400TS, ER400RS & ER400TRS 1-1.doc
Easy -Radio ER400TS Transmitter, ER400RS Receiver & ER400TRS Transceiver
Copyright LPRS 2003. March2004
Page 14 of 15