PI P192-S User manual

APPLICATION NOTE
Research
P192-S Telemetry radio

2Pi P192-S Telemetry Radio Application Note
Pi P192-S Telemetry Radio
Application Note

3
Disclaimer
Pi Research makes no representation or warranties of any kind whatsoever with respect
to the contents hereof and specifically disclaims any implied warranties of merchantability
or fitness for any particular purpose. Pi Research shall not be liable for any errors
contained herein or for incidental or consequential damages in connection with the
furnishing, performance or use of the software, associated hardware, or this written
material.
Pi Research reserves the right to revise this publication from time to time, and to make
changes in the content hereof without obligation to notify any person of such revision or
changes.
A copy of the Pi Research Terms and Conditions of Sale is available on request, and
includes a declaration of the warranty and limitation of liability which apply to
all Pi Research products and services.
Health and Safety information
Under the terms of European and UK Health and Safety Legislation, Pi Research is
required to classify any hazardous materials in the products it supplies and to provide
relevant safety information to users.
Any hazardous materials in Pi products are clearly marked with appropriate symbols.
Product Safety Data Sheets relating to these materials are available on request.

4Pi P192-S Telemetry Radio Application Note
Introduction .............................................................................................. 6
Licensing information ..................................................................... 6
Car radio installation ............................................................................... 7
Installing a P192-S radio in a car ................................................... 7
Car radio transmit antenna ............................................................. 8
P192-S as a pit receiver......................................................................... 11
Power supply ................................................................................ 11
Pit data loom ................................................................................. 11
Diversity receiving function .......................................................... 12
Pit receiver antenna ..................................................................... 13
Connecting antennas ............................................................................ 14
Configuring the P192-S ......................................................................... 15
Radio configuration utility ............................................................. 15
P192-S status LED’s .............................................................................. 20
Serial Interface ....................................................................................... 21
Baud rate setting .......................................................................... 21
Forward error correction (FEC) .................................................... 21
Pi Sigma stream optimization ....................................................... 22
Minimisation of the Message Size ................................................ 23
Transmit buffer ....................................................................................... 24
CTS (Clear to send) ............................................................................... 25
Specifications ......................................................................................... 26
Connector information .......................................................................... 27
Connector details .......................................................................... 27
Data connector pin details ............................................................ 27
Contents

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Parts numbering .................................................................................... 28
Dimensions ............................................................................................. 29
Declaration of conformity ..................................................................... 30
Conditions Of Use ........................................................................ 31
FCC Authorisation ........................................................................ 31
Contact information ............................................................................... 32

6Pi P192-S Telemetry Radio Application Note
Introduction
The Pi telemetry system provides reliable data transmission from a car to the pits as the
car travels around the track. A P192-S radio in the car transmits the telemetry data and a
P192-S radio in the pits receives the transmissions. The received telemetry data is passed
to a PC for processing and display.
The P192-S radio has no user controls and the setup is carried out by Pi Research. The
frequency and transmit power can be programmed via the Pi Programming software with
the programming lead connected in line with the radio and to a PC’s comm port.
Licensing information
Before you use the telemetry system you must apply to the appropriate radio licensing
authority for the frequency and power setting that you intend to use.

7
Car radio installation
Installing a P192-S
radio in a car
The P192-S radio needs a power supply between 12 to 30 volts DC. If you are connecting
the telemetry system to a Pi System, the radio loom connects battery power to the radio
system.
If you are building your own wiring loom for the telemetry system refer to the section
Connector information .
CAUTION: The anti-vibration mounts supplied MUST BE used to mount the radio.
The radio will not function correctly, may be damaged, and its warranty will be
void if the anti-vibrations mounts are not used.
When installing the P192-S radio in a car:
■the anti-vibration mounts supplied MUST BE used to mount the radio. The
radio will not function correctly if the anti-vibration mounts are not used;
■select a position where the radio will not be in constant contact with water,
fuel or oil;
■make sure that the radio will not be affected by heat soak. Ensure that air
can flow over the radio to keep it below 55°C; Insufficient airflow will
overheat the transmitter, and the radio will shut down until the temperature
drops sufficiently.
■make sure that the radio is electrically isolated from the chassis and all
surrounding parts;
■ensure connector casing is isolated from all loom connections and the loom
screen;
■try not to place the radio near sources of electrical interference e.g. ignition
coils, plug leads, ECMs, alternators and other radio transmitters.

8Pi P192-S Telemetry Radio Application Note
Data loom
When installing the data loom, you should avoid running it next to sources of interference,
i.e. ignition coils, plug leads, alternators, fuel pumps and ECMs. If the loom has to run near
any of these, then try to avoid parallel runs.
Car radio transmit
antenna
Ground planes
The transmit antenna needs a suitable ground plane to operate efficiently. The ground
plane is a conductive material placed at the base of the antenna and increases the
efficiency of the antenna by reducing the amount of power that is reflected back into the
radio module.
Generally, the construction and shape of a race car does not allow for a suitable ground
plane. To use your telemetry equipment effectively, you may have to make a suitable
ground plane.
Each antenna comes with an installation kit that includes a piece of self-adhesive copper
foil which you can use to make a ground plane.
When making a ground plane, you should consider the following points:
■The antenna should be mounted in a vertical position in the centre of the
ground plane and at least 150mm (6 inches) away from any vertical piece
of the car or other antenna;
■The ground plane should be circular and have a radius at least equal to the
length of the antenna;
■The ground plane must not make electrical contact with any part of the
vehicle chassis that is likely to conduct, for example, carbon fibre.

9
Fibre glass body panels
To fit the antenna to a fibre glass body panel:
1Locate a suitable panel, that can be removed easily for access to the antenna
loom.
2As fibre glass is electrically non-conducting, you can stick the copper foil
directly to the underside of the panel.
3Tighten the TNC connector of the antenna, ensuring that it makes electrical
contact with the copper foil.
4Ensure that the copper foil does not make contact with any part of the chassis
that is likely to conduct.
Antenna
TNC bulkhead
connector
Insulating layer
Insulating washer
Copper foil
Locking washer
Fixing nut
TNC terminated
feed cable
Body panel
Insulating washer
Antenna installation detail

10 Pi P192-S Telemetry Radio Application Note
Carbon fibre chassis panels
1Locate a suitable panel that can be removed easily for access to the antenna
loom. An ideal panel is over the front suspension dampers.
2Make a bracket from metal or carbon fibre that will hold the antenna vertical.
Fix the bracket to the chassis.
3Stick an insulating layer of ‘tank tape’ to the underside of the bracket. Make
sure that it is of a larger diameter than the copper foil for the ground plane.
4Stick the copper foil to the underside of the insulating layer.
5Tighten the TNC connector of the antenna, ensuring that it makes electrical
contact with the copper foil.
6Ensure that the copper foil does not make contact with any part of the chassis
that is likely to conduct.
7Drill a hole in the panel for the antenna to pass through.
Antenna feed loom
If you are going to use your own antenna feed loom, it should be a high quality coaxial
cable, with a stranded inner core. We recommend that you use RG58 50 ohm coaxial
cable.
For best results, use crimp TNC connectors for both the radio and antenna ends of the
feed cable.
WARNING: It is important that the TNC connectors of the feed loom do not vibrate
against any other conducting surfaces such as Lemo connectors or the chassis
floor, as this will result in radio frequency noise and a loss of signal.