rx1-173.200-10 Radiometrix Ltd, rx1-173.200-10 Datasheet - Page 11

• Manufacturer Part Number: rx1-173.200-10
• Description: Left Tx1 Transmitter Right Rx1receiver
• Manufacturer: Radiometrix Ltd

Integral antenna summary:
Tamper-proof integral antenna
Where the RX1 is used in alarm applications it may sometimes be necessary to provide a warning if any
attempt is made to remove or disable its antenna. A typical solution to this problem is as follows:
In normal operation the output will have a resistance to ground of R1+R2. If the antenna is shorted to
ground it will show R2 only, and if the antenna is cut it will be open-circuit.
R1 and R2 may be any value over 1k . All track lengths should be kept to a minimum and the output
may need to be decoupled in some cases to avoid noise being injected into the antenna from the
following circuitry.
Radiometrix Ltd., TX1 & RX1 Data Sheet
Whip antenna
Helical antenna
Loop antenna
410mm @ 173MHz
hairpin loop
1/4 wave
antenna
1n
Ultimate performance
Ease of design set-up
Size
Immunity to proximity effects
R1
Fig.11: Tamper-proof antenna arrangement
C
Fig.10: integral antenna configurations
tune
1 2 3
RX1
R2
RF GND
RF
R
F
C
R
F
match
capacitors may be variable or fixed
(values depend on loop dimensions)
35-40 turns wire spring
length 120mm, dia 10mm
trim wire length or expand coil for
best results
track width = 1mm
min. area 500mm
wire, rod, PCB track
or a combination of these
length(mm) = 71250 / freq(MHz)
to comparator circuit, etc.
4 5 6 7
whip
***
***
**
*
8 9
helical
***
**
**
2
*
loop
***
**
*
*
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