T7 / R7
T7G / R7G
FM 433MHz Narrow Band
Reducing Power to 10mW
RSSI Values
The R7 / R7G receiver RSSI outputs provide a DC
output proportional to the RF signal. The table
below shows the typical RSSI value depending on
the Signal strength.
If the T7G transmitter will be used with an efficient
antenna in countries where only 10mW radiated
power is allowed, then a simple resistive network
on the output of the module will attenuate the
power down to this level.
RF Signal
Strength/dBm
Circuit Diagram
R7 (V)
GR7 (V)
-130
-120
-110
-100
-90
1.03
1.06
1.16
1.34
1.59
1.78
1.81
1.81
2.17
2.45
2.52
2.52
1.25
1.32
1.46
1.69
1.96
2.2
2.47
2.5
2.5
-
T7B
1
2
3
4
5
TO
ANTENNA
22ohm
-80
220 ohm
220 ohm
-70
-60
When laying out this network, keep all tracks as
short as possible, especially ground paths and
use 50 ohm track impedances when connecting to
and from this network. This impedance can be
realised on 1.6mm FR4 pcb by using a track width
of 2.5mm.
-50
-40
-30
-
-20
-
Notice that the region between –80 to –60 is with
the receiver agc operating. If required, a receiver
version with agc disabled can be provided as a
factory Pre-set option. This would linear-rise the
RSSI curve.
Mechanical Dimensions
3.0 mm
8.30mm
31.5 mm
48mm
4.65mm
CE
10.5 mm
17mm
T7 / T7G
R7 / R7G
pin spacing 2.54mm
30.48mm
1
2
3
4
5
1.5mm
3.5mm
20.32 mm
1
2
3 4 5 6 7
Pin spacings 2.54 mm
Pin Dia 0.5mm
Pin spacings 2.54 mm
Pin Dia 0.5mm
All dimensions +/- 0.5mm
pin 1 is 2.33mm from edge of module
All dimensions +/- 0.5mm
R F Solutions Ltd.,
Unit 21, Cliffe Industrial Estate,
South Street, Lewes,
E. Sussex. BN8 6JL, England
Tel: +44 (0)1273 898 000
Email : sales@rfsolutions.co.uk
Fax: +44 (0)1273 480 661
http://www.rfsolutions.co.uk
Information contained in this document is believed to be accurate , however no representation or warranty is given and no liability is assumed by R.F. Solutions Ltd. With
respect to the accuracy of such information. Use of R.F.Solutions as critical components in life support systems is not authorised except with express written approval from R.F.Solutions Ltd.
DS307-7 Oct 05
©2004 REG No 277 4001, England.
Page 7
RFSOLUTIONS [ RFSOLUTIONS.LTD ]
