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FoxTrak Basic (Rev FT-1111) is
now revised to:
Foxtrak-0416
(click to visit present project page)
The
Schematic
&
Technical
Information
presented
here
generates
an APRS
signal
with very
little
effort.
It’s a
TinyTrak
type of
tracker
hardware
with small
changes,
where all
functions
are
controlled
by
PIC16F84A.
The
position
data in
NMEA
format ( $GPRMC
)
delivered
from a GPS
is decoded
and a 1200 bps
packet
radio
signal is
generated
from it.
This can
be fed
directly
into a
Radio
Transmitter
without
the need
of an
expensive
TNC.
Because of
not having
enough
program
memory
left on
PIC &
to make
hardware
simple,
circuit
does not
decode
received
APRS
signals.
This
APRS
interface
has a
serial
interface
for
connecting
to the GPS
and for
configuration
of user
parameters
into
PIC’s
memory.
The
main new
features
compared
to
TinyTrak (Byonics)
besides
some
hardware
variations
is, speed
dependable
beacon
rates and
beacon
transmissions
at major
course
changes.
Suitable
Firmware
for this
type of
hardware is
developed
by many radio
amateurs.
One tested
in this
project is
by DK7IN
who has
also made
a nice
Linux based
configuration
utility to
write user
parameters
in PIC.
However,
TinyTrak's
windows
configuration
utility
may also
be used
for the
same
purpose. A
Linux
version is
available
for
download.
Other
firmware,
developed
by PE1RXQ
may also
be used
with added
operational
benefits.
However,
this was
not tried
by me on
first
proto
board.
There is
also a way
to convert
this
tracker
into a
Data
Tracker,
please
visit the
links
provided
below,
where more
information
may
be found.
In
addition
to above
basic
hardware
&
pre-programmed
PIC
supplied
with kits,
my main
intention
is to make
available
economical
APRS
tracker
hardware/PCBs
to Radio
amateurs,
who wish
to further
develop
their own
type of
APRS
Trackers.
Since
FoxTrak
may be
configured
for
various
firmware,
you may
update
FoxTrak
with a better
&
smarter
Firmware
& if
necessary,
change the PIC,
to
16F628A.
The Basic
hardware
remains
the same.
Like
TinyTrak
3+, this
tracker
also uses
larger 5V
regulator
to supply
GPS power.
With
suitable
header
installations,
you may
supply GPS
with
either 12V
or 5V.
FoxTrak
also
includes
an Instant
Transmit
Push
Button.
FoxTrak
is
designed
on a
Double
Sided PTH
PCB &
measures
only 7cm x
4.5cm. I
am using
standard
right
angle D9F
& M
connectors.
FoxTrak
also comes
with Null
Modem
Adaptor.
This
adaptor
uses two
R/A D9F connectors & has a PTH PCB.
Both
FoxTrak D9
Sockets,
Radio side
&
RS232/GPS
side, have
exactly
the same
connection
plan as
used with
TinyTrak
& Open
tracker
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