Other Projects

AD9852 DDS Source Click to enlarge 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

AD9850 DDS Board PCB layout for the old design, originally published in Radcom November 2000

Multi Purpose PIC Controller - as published in RadCom June 2011

VHF Synthesizer Module - VHF Synthesizer Module -
Small standalone module for up to 170MHz. Controlled via RS232 serial interface with ASCII commands
VHFSynthModule.zip Hi-res diagrams, design utilities, PCB, PIC Code Bugs, modifications, corrections
SOLD OUT No more mini kits available - sri folks !

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.
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.

Alcatel 'White Box' modifications for 24GHz

Beacon Keyer Modules, - and now a NEW version with analogue input channel for remote voltage measurements.
Supplied Ready-made, or homebrew your own

RTTY Keyboard Adapter small PIC based adapter for using a PC keyboard to generate raw 5V logic level 45 baud RTTY data. Can be used in parallel with the NUE-PSK Modem with a subset of common control codes. Includes a type ahead buffer to allow for fast typists
PCB layouts, circuit diagram and PIC .HEX code. I'm not making the source code availalble, SRI Folks !

DTMF Remote Controller
DTMF Remote control over a telephone line.
This article was first published in Radio Communication in August 2001

700W Switch Mode Tx for 137kHz Click to enlarge Medium Power (~ 40W) Linear amplifier for 137kHz.
Simple design running from 26V supply using surplus FETs and ferrites.

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

Class E Tx Switching Waveform

1.8MHz class-C Power Amplifier with a few quirks.
Single IRF540 Mosfet design running from 12V. Delivers more power, more efficiently, than the design suggests it should.

Breadboard 400 Watt plus Class E Transmitter for 500kHz,
Low cost, high efficiency, running from 50 Volt rail

Software Defined Radio Projects Tx and Rx software, I/Q Up and Down Converters, SDR Tests

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

JNT001 Transverter interface for IC202, FT290 or similar. PIN Diode Tx / Rx switching, switched power rails and 21V vsupply for coax relays. This rather ancient design first appeared in 1992

JNT004 1296MHz Transverter ModuleThis was originally published in RadCom June/July 1994

OPA_AllPAss.xls All-Pass network design spreadsheet

144MHz Direct Conversion Receiver
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

NoiseMeter.zip Modern Soundcard Replacement for the G4COM Noise Figure Alignment aid. With software writetn by G3PLX

Audio VOX Circuits Two simple circuits for controlling Tx/Rx switching on a transceiver for datamode software.
Avoid complications with COM port interfacing

Evanescent Filters for 3400MHz and 5760MHz Easily constructed narrow bandpass filters built using standard size waveguide

50-75MHz Bandpass filter with some interesting characteristics
For a frequency converter feeding a wideband Software Defined Radio like the SDR-IQ

Digital Rotator Display as published in Short Circuits, RadCom, Jan 2009

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