Other Projects
Beacon Keyer Modules, - and now a NEW version with analogue input channel for remote voltage measurements.
AD9850 DDS Board PCB layout for the old design, originally published in Radcom November 2000
Verticom Synthesizer Control These Synths were originally described by G4FRE/WW2R.
Alcatel 'White Box' modifications for 24GHz
DTMF Remote Controller
JNT004 1296MHz Transverter ModuleThis was originally published in RadCom June/July 1994
OPA_AllPAss.xls All-Pass network design spreadsheet
1.8MHz class-C Power Amplifier with a few quirks.
144MHz Direct Conversion Receiver
Audio VOX Circuits Two simple circuits for controlling Tx/Rx switching on a transceiver
for datamode software.
Evanescent Filters for 3400MHz and 5760MHz Easily constructed
narrow bandpass filters built using standard size waveguide
50-75MHz Bandpass filter with some interesting characteristics
Digital Rotator Display as published in Short Circuits, RadCom, Jan 2009
Software Defined Radio Projects Tx and Rx software,
I/Q Up and Down Converters, SDR Tests
Supplied Ready-made, or homebrew your own
AD9852 DDS Module
A single PCB module for an RF source for up to around 100MHz with control of
frequency, amplitude, phase and other 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
See the Software page for driving this module
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
Upconverters
Several tested IQ Upconverter designs including one for 145MHz that could form the basis of a microwave transverter driver.
Pointers and suggestions to other ideas...
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
Includes an all-pass 0/90 degree phasing network for single audio (non I/Q) outputs
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
Avoid complications with COM port interfacing
For a frequency converter feeding a wideband Software Defined Radio like the SDR-IQ