Other Projects
AD9850 DDS Board PCB layout for the old design, originally published in Radcom November 2000
L-Band Synthesizer + PIC code The Author of the "Cheap and Simple Synthesizer" published in Scatterpoint has kindly allowed his article to appear on this website. The original PIC code can be found here, as well as code for controlling the synthesizer with a rotary encoder and Liquid Crystal Display
Verticom Synthesizer Control These Synths were originally described by G4FRE/WW2R.
DTMF Remote Controller
LF Upconverter for translating soundcard output direct to LF. Includes an all-pass 0/90 degree phasing network for single audio (non I/Q) outputs. -
OPA_AllPAss.xls All-Pass network design spreadsheet
1.8MHz class-C Power Amplifier with a few quirks.
144MHz Direct Conversion Receiver
Software Defined Radio
The basics behind SDR techniques.
50-75MHz Bandpass filter with some interesting characteristics
List of Maximal Length Shift Register taps
Now Properly formatted text files with [cr][lf] terminators
New File Encryption Software for Windows
Simple, straightforward and very strong protection for critical files against unauthorised access
AD9852 DDS Module
A single PCB module that can generate frequencies
up to approx 80MHz with control of
frequency, amplitude, phase and other device operating parameters over a serial
/ RS232 interface with simple text-based commands. The on-board PIC controller
can be reprogrammed for a multitude of frequency generation
and modulation tasks. --
The updated Mark 2 version --
PCB Layout - if you want to roll your own
Beware, When tuned to 1575.375MHz, it will disable your GPS locked source from quite a long way away.
Here is an alternative PIC controller to that described, that allows control with ASCII commands on an RS232 interface. Also a utility (with VB source code) for calculating the values to be sent.
DTMF Remote control over a telephone line.
This article was first published in Radio Communication in August 2001
700 Watt Switch Mode Transmitter for 137kHz
High efficiency LF transmitter design running direct from rectified mains supply.
Reproduced with permission. Copyright
ARRL 2002, all rights reserved.
This material originally appeared in QEX: Forum for Communications Experimenters
www.arrl.org/qex
Single IRF540 Mosfet design running from 12V. Delivers more power, more efficiently, than the design suggests it should.
Simple design with I/Q outputs for the RF front end of a sofware defined radio
Also useable stand-alone unit for beacon monitoring and signal measurements .
This article was first published in Radio Communication November 2004
A presentation given at the HF Convention in 2002
(Some hardware details are a bit are out of date now)
Amateur Use of Novel Signalling Methods at Low Frequencies
A poster presented at The IEE Conference, London on 24/25 October 2002 entitled
"Getting the Most out of the Radio Spectrum"
For a frequency converter feeding a wideband Software Defined Radio like the SDR-IQ
I ought to credit someone with this, but can't remember where it came from, or find the URL