The antenna choice and position directly controls the system range. Keep it clear of other metal in the
system, particularly the 'hot' end. The best position by far, is sticking out the top of the product. This is often
not desirable for practical/ergonomic reasons thus a compromise may need to be reached. If an internal
antenna must be used, try to keep it away from other metal components, particularly large ones like
transformers, batteries and PCB tracks/earth plane. The space around the antenna is as important as the
antenna itself.
410mm @ 173MHz
R
wire, rod, PCB track
or a combination of these
F
Whip antenna
length(mm) = 71250 / freq(MHz)
35-40 turns wire spring
length 120mm, dia 10mm
R
F
trim wire length or expand coil for
best results
Helical antenna
track width = 1mm
min. area 500mm2
RF
capacitors may be variable or fixed
(values depend on loop dimensions)
Cmatch
C
tune
RF GND
Loop antenna
Figure 7: Antenna types
Ordering Information:
Part No.
Description Channel Frequencies (MHz)
RF
power
(mW)
Channel
Spacing
(kHz)
Data
rate
kbps
LMT1-144-5
LMR1-144-5
Transmitter
100
CH0:144.000 – CH31:144.775
Receiver
25
5
LMT1-151-5
LMR1-151-5
Transmitter
100
100
CH0:150.825 – CH31:151.600
Receiver
25
5
5
LMT1-151-5-12k5-MURS
LMR1-151-5-12k5-MURS
Transmitter
Receiver
CH0:150.820, CH1:150.880,
CH2:151.940, CH3:154.570,
CH4:154.600
12.5
25
LMT1-156.525-PM
Transmitter
156.525MHz
100
10
2.6V
pk-pk
2.1kHz
LMT1-173-5
LMR1-173-5
Transmitter
Receiver
CH0:173.250 – CH3:173.325
CH4 – CH7:173.225
25
5
CH8 – CH31:173.325
LMT1-173-5-12k5-FCC
LMR1-173-5-12k5-FCC
Transmitter
Receiver
CH0:173.20375, CH1:173.210,
CH2:173.2375, CH3:173.2875,
CH4:173.3125, CH5:173.3375,
CH6:173.3625, CH7:173.39625
100
12.5
25
5
5
LMT1-xxx-5
LMR1-xxx-5
Where xxx is any 2MHz band from 130MHz to-
180MHz
10/100
Radiometrix Ltd
LMT1/LMR1 Data Sheet
page 9
RADIOMETRIX [ RADIOMETRIX LTD ]
