DDS based VHF Beacon Driver
Design and construction of the AD9852 based driver used on the new GB3VHF 144MHz beacon.
A multipurpose VHF beacon driver module for JT65, CW and RTTY and
PIC Code for driving Beacons like GB3VHF and the 40-70MHz GB3RAL
Includes the code for generating JT65 from data generated using the
JT65CODE programme and for
reading Motorola compatible binary data from various GPS modules
Utilities for programming DDS sources for use in beacons - calculating frequency codes, formatting JT65 symbols from JT65CODE.
Fractional-N Synthesizer Source and driver for 144MHz beacons as used for GB3WGI.
PCB Layouts for direct printing to Acetate / Press-N-Peel
Programming and using Fractional-N Synthesizers with MFSK / WSJT Modes
JTxx on the LMX2541 PIC Assembly Code and symbol generators for generating
JT4 and JT65 with the LMX2541 Fractional-N Synthesizer
PI4 Support for PIC controllers for LMX2541 and LMX2470 Fract-N synthesizers and AD9852 DDS
Includes Symbol generator, with source code for generating PI4Symbs.INC and Excel spreadsheet for calculating the constants
needed for different crystal frequencies
Self Contained Beacon Driver with integral GPS receiver and Fractional-N
synthesizer. Includes an optional driver amplifer for V/UHF.
A 16F628 PIC, AD9852 DDS and Motorola-Oncore GPS module make up a Driver for generating WSPR signals.
Message and frequency data needs are prepared off-line and blown into the PIC for a standalone source.
Includes utilities for running WSPR.EXE (see Joe's website ) to
generate tone data and then convert to a form for direct import to PIC assembler.
LDPC Coding Process Coding for all the new WSJT-X modes that use
Low Density Parity Check (LDPC) codes: FT8, FT4, FST4, FST4W and MSK144
Coding of these modes have much in common, as well as some subtle differences
The WSPR Coding Process Encoding and generating WSPR messages.
GENWSPR.EXE Self-contained programme for generating WSPR symbol data.
Download and run from a command line - for example 'GENWSPR G4JNT IO90 33
Unlike WSPR.EXE, this prog is not fussy about upper/lower case data in its entry, and flags an
error message if you try to enter the wrong number of parameters. This is my first play with C-Coding and is
the result of a lot of time spent learning the language; I took some code found on the web that encoded WSPR
data ('fraid I can't remember where or who to credit!) and added the rest. It gives the same answers as Joe's
software does, and also cures a bug in WSP2INC that generates an incorrect final pair of symbols. Please report
any bugs or errors found.
FST4 Beacon Source FST4 is a new mode aimed at the LF/MF bands with data rates
as slow as 0.089 Baud.
Using Gaussian MFSK, it requires a new technique to generate the sliding frequency transistion.
Support including PIC code and design utilities are here FST4Beacon.zip
JT4 for the uKUG RDDS Module.Full Description and operating details
-- also suitable for any other frequency generator based on the AD9851 DDS chip --
Needs a GPS Module or other source of timing information. Motorola Binary or NMEA format is acceptable,
and optionally a 1 PPS signal. The PIC software has to be customised at compile time, so only source code and instructions will be
available to do-it-yourselfers
BUT.... a programmed 16F628 PIC can be supplied. You supply CW message, JT4 code, GPS engine, data
polarity etc and it will be customised to your requirements.
Plug this into the RDDS board in place of the PIC supplied,
connect the timing data source and away you go.
PIC Based DDS + JT4 Generator for low frequency subcarrier type use,
eg. optical communications experiments
New Improved version, for JT4 or JT65
LF DDS Beacon Source.
Position Reporting using WSJT Modes Using Weak signal modes to
transmit high resolution positional data. Lat/long from GPS data is compressed into a WSJT compatible message
and sent using JT4 or JT9 modulation.
Generating MSK144 using a PIC and DDS.
External DDS Chip for direct MSK144 generation, or I/Q free running source for quadrature upconverter. Includes
a complete 1.3/2.3GHz beacon source design.
A suggested Tone / Frequency Allocation when using JT4G on Microwave Beacons
For other MGM modes, A more generalised suggestion forTone Frequencies
Standardises JT4G tuning point, plain-carrier and on-off or FSK CW tone frequencies.
PIC Assembly code for JT4 - RDDS
Programme your own 16F628. With two example include files to work from
GENJT4 and GENJT9 Symbol Generation Utilities for JT4 and JT9.
Unzip and run, preferably from a command line. Enter your 13 character data string - it will go away and
generate JT4SYMBS.INC or JT9SYMBS.INC
JT4 Frequency Calculator
A bit more friendly than a spreadsheet, this windows prog calculates the frequency data for programming into the
PIC in a format suitable for direct copy-and-pasting into assembly files. Can be used for normal / direct and reverse DDS use.
Full details of the internal coding of JT4 messages.
Full details of the internal coding of JT9 messages.
JT4 Symbol to PIC Conversion
A bit more on using a PIC / DDS for JT4
Full details of the internal coding of ISCAT messages.
Back to Main Beacons page
Back to Index