AM Transmitter Module
MKT1-XXX
Version 3.0
Page 3 of 4
AM or FM Low Power Radio Modules for 100 to 1000 MHz
Designers and Manufactueres of Quality Transmitters, Receivers and Transceivers
Connection Details
MKT1
Transmitter
1
2
Component
Side
Figure 1: MKT1 Transmitter
Application Information
Antenna Design
The design and positioning of the antenna is as crucial
as the module performance itself in achieving a good
wireless system range. The following will assist the
designer in maximising system performance.
The antenna should be kept as far away from sources of
electrical interference as physically possible. If
necessary, additional power line decoupling capacitors
should be placed close to the module.
The antenna ‘hot end’ should be kept clear of any
objects, especially any metal as this can severely restrict
the efficiency of the antenna to transmit power. Any
earth planes restricting the radiation path to the antenna
will also have the same effect.
Best range is achieved with either a straight piece of
wire, rod or PCB track @ ¼ wavelength (15.5cm @
433.92MHz). Further range may be achieved if the ¼
wave antenna is placed perpendicular in the middle of a
solid earth plane measuring at least 16cm radius. In this
case, the antenna should be connected to the module via
some 50 ohm characteristic impedance coax.
Pin Description
Data (pin 1)
CMOS/TTL compatible input. Must be driven with
appropriate current limiting resistor to provide the
module with 5mA.
GND (pin2)
Ground connection, preferably connected to a solid
ground plane.
General Information
The MKT1-XXX requires a current limiting resistor
(Rd) to source the module with the correct drive
current. The following values of Rd can be used with
the module depending on the drive voltage:
Drive Voltage = 1.5
–3.7V then Rd = 51 to 300
Drive Voltage = 7
– 13 V then Rd = 1K0 typical
ANTENNA
220pF
Rd
MKT1
1
2
drive current
drive
voltage
Signal From
Encoder
Figure 2: Drive Circuit Required For MKT1
Transmitter Module
PIN 2
PIN 1
C1
Loop Antenna Area
600mm
2
PIN 1
C1 = 2.2pF @ 418MHz
C1 = 1pF @ 433MHz
15.5cm @ 433MHz
Loop Antenna
Whip Antenna
Figure 3: Antenna Configurations To Be Used With
The MKT1 Transmitter Module