rx1m-169-5-12k5 Radiometrix Ltd, rx1m-169-5-12k5 Datasheet - Page 5

• Manufacturer Part Number: rx1m-169-5-12k5
• Description: 12.5khz Channel 12.5khz Channel Vhf High Power Tx
• Manufacturer: Radiometrix Ltd

Power supply requirements
The ENT1 has a built-in regulator which delivers a constant 3.3V to the transmitter frequency control
circuitry when the external supply voltage is 3.4V or greater. This ensures constant frequency stability
and removes the need for external supply decoupling except in cases where the supply rail is extremely
poor (ripple/noise content >0.1V
TX modulation requirements
The module is factory-set to produce the specified FM deviation with a TXD input to pin 14 of 5V
amplitude, i.e. 0V “low”, 5V “high
If the data input level is greater than 5V, a resistor must be added in series with the TXD input to limit
the modulating input voltage to a maximum of 5V on pin 7. TXD input resistance is 100k
Expected range
Predicting the range obtainable in any given situation is notoriously difficult since there are many
factors involved. The main ones to consider are as follows:
The following are typical examples – but range tests should always be performed before assuming that
a particular range can be achieved in a given situation:
Note:
The ENT1’s TXD input is normally driven directly by logic levels but will also accept analogue drive
(e.g. 2-tone signalling). In this case it is recommended that TXD (pin 14) be DC-biased to 2.5V approx.
with the modulation ac-coupled and limited to a maximum of 5V
Although the modulation bandwidth of the ENT1 extends down to DC it is not advisable to use data
containing a DC component. This is because frequency errors and drifts between the transmitter and
receiver occur in normal operation, resulting in DC offset errors on the receiver’s audio output.
Radiometrix Ltd.,
Type and location of antennas in use
Type of terrain and degree of obstruction of the link path
Sources of interference affecting the receiver
“Dead” spots caused by signal reflections from nearby conductive objects
Data rate and degree of filtering employed
Data rate
1.2kbps
The figure for 1.2kbps assumes that the receiver bandwidth has been suitably reduced by
utilising an outboard sallen-key active audio filter and data slicer or similar arrangement.
Tx antenna
half-wave
p-p
).
Applications information
Rx antenna
half-wave
ENT1 high power transmitter data sheet
Environment
rural/open
p-p
to minimise distortion over the link.
10-15km
Range
to ground.
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