14 Oct 2020

Website runs 24/7 on 5 watts of power!

Have you got any unwanted electronics? Components, projects, radios, equipment?
Recycle by donating them to me for re-use.
I undertake all shipping costs!

Thanks Earl from Canada, for the components exchange!
Thanks Alex from Italy, for his kind offer!
Thanks Joerg from Germany, for his kind donation!

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Theory, information and tutorials
Natural radio
Electronics and RF techniques
Circuits and Projects
Poor man's laboratory equipment
Online software

Mechanical work
Useful Links
Contact me

All HF bands transmitter experiment
Rigs selector and automatic antenna switch for your shack

               If you like my site you could consider donating a small amount to keep the projects updated. Thanks!

Theory, information and tutorials
5-9 Report (archived Greek amateur radio magazine)
Set up your own dial-up server (vintage networking through telcos)
RF radiation and electroagnetic field safety
Assembly tutorial and information
Diodes evaluation for crystal sets - A simple test
A tribute to the watch movement
A tribute to the wind-up gramophone engine
Linear UHF vacuum tube circuits
Vacuum tube television
General diode applications
All diodes transceiver
Passive crystal receivers
Tunnel diodes
Varactor diodes
Schottkey diodes
Rectifier diode audio amplifier
Passive DSB transmitter
Passive CW transmitter
Ferrite core mixers
Magnetic amplifiers
Electromechanical transmitters and receivers
Neon lamps
Radar history
The phasitron tube
Thermoelectric generator
Analog computers
Logic gates technology
My designs on electromechanical transmitters for LW
TV transmitters
SSB transistorized CB
Barlow Wadley loop
Radio spectrum frequency allocation chart
dBm, mw, Vpp, Vp, Veff conversion table
Optimum wire size for RF coils
Observations on ferrite rod antennas
Designing wideband transformers for HF and VHF power amplifiers
Crystal parameter measurement and ladder crystal filter design
Quartz crystal parameter measurement
Crystal filters with variable bandwidth and constant center frequency
Easy to build crystal ladder filters (page26)
Ultra low noise active devices on a budget
74LSxx series chips internal schematics
Common varicaps in radio
RF mixers explained. Part 1, part 2 and part 3.
Understanding mixer products
AM/SSB modulation and peak envelope detector
Calculating transmitter efficiency
Measuring transmitter power, do and don't
Harmonics generation using step recovery diodes (HP)
Understanding noise types in oscillators
Motorola master selection guide - Small signal BJTs, FETs and diodes
Voltage controlled capacitance without varactors
IARU region 1 VHF and up band plan
IARU region 1 HF Europe band plan
IARU region 1 HF band plan
Electronics and RF techniques SV3ORA Natural radio
Idea for a simple wire recorder
Hacking the GSM codecs to pass FSK data through
Lead-free solder comparison. SAC305 vs SnCxPlus07
Wheatstone bridge splitter/combiner construction and measurements
Using capacitors as varicaps
Holder for RF toroids
Transformers winding on HF in-phase splitter
BJT negistor applications
Salvaging electronics components for QRP projects
Common mode chokes in boost converters
Exponential RF amplifier for reducing harmonics without filtering
Crystal oscillator oscillates in more than one frequencies simultaneously!
An adaptable crystal set that has it all?
Homebrew your own SiC LED
Reliability of data storage media
A generalized prototype board for digital electronics work
The simplest way to program and read the PIC16F84 MCU

Measuring and selecting the actual received frequency in regenerative and direct conversion receivers
Ultra narrowband adjustable shape and bandwidth crystal phasing filter
Making precision PCB coils
Experiments on circuits on paper - Dwawn resistors
Homemade film capacitors
The sounds of the earth and other natural sources and simple equipment
E-field VLF natural radio receiver
H-field VLF/ELF/ULF natural radio receiver (in development)
Circuits and Projects SV3ORA
RF electronics

Rigs selector and automatic antenna switch for your shack
All HF bands transmitter (experiment)
Installing a mechanical SSB filter on the FRG-7
Tune your FRG-7 to true SSB
Correcting the fine tune in the FRG-7
RF power switch for your rigs
Classic 40 CW/AM transmitter
Emergency transmitter - A 8-components high-power 40m/30m transmitter to get you quickly on the air
The magical audio filter refined
The brilliant "miniVFO". As stable as a crystal and mini!
Dimming the panel lights on the Yaesu FT-301
Add general HF receive coverage to the Yaesu FT-301
HF DSB walkie talkie
Simple all bands superhet CW receiver
DDS DSB/AM receiver 0-60MHz
QRP audio amplifier
Mini AM transmitter
The all waves RX powered by 1.5v
The "Super VFO". As stable as a crystal
Simple MCU-free HF frequency counter
Improving the Albrecht AE2990AFS
Easy and reliable bfo
A cheap and easy all hf bands transceiver
A broadband concept receiver that will amaze you
HF+6m active antenna for the Kenwood TH-F6/TH-F7
HF all bands handheld transceiver for the radio amateur
An easy to build UHF TV modulator
Single signal reflexed regenerative receiver
All-bands single-signal filtered regenerative detector
Universal, very low distortion, HF broadband crystal oscillator
Vacuum tube microwave oscillator (Greek)
All about LPD/PMR transceivers (Greek only)
Wide range quadrature oscillator without DDS
easy40 - A 14-components high-power transmitter to get you quickly on the air
A 2-components oscillator
High dynamic range broadband LNA for handheld transceivers
Preamplifier switching and bypassing using RF as control
HF directional coupler
Broadband CW QRPp HF transmitter
Ultra low noise, low distortion, general purpose LF/MF/HF oscillator
All HF bands low distortion sinusoidal XO
The ultimate QRP HF transceiver
A simple, good quality UHF TV modulator
The S53MV ZIF microwave transceivers reborn

An easy to build all HF bands discrete SSB transceiver
In-phase splitter/combiner
4:1 balanced to unbalanced balun
10GHz gunnplexer (in development)
Magnetic receiver (in development)
Fine tuning the SM0VPO HF amplifier for better performance
An ultimate quality shortwave transceiver (in development)
The fully transistorized radio project
Smart KIT 1W FM transmitter reverse engineered
Single span, high spectral purity oscillator 3KHz-30MHz (in development)
A simple to assemble regenerative SW receiver

My 10GHz SDR phasing SSB transceiver
(in development)

HF all-band tuneable bandpass filter
1-30MHz deluxe crystal controlled CW/CDW transmitter
1-30MHz ultra low noise and distortion crystal oscillator
Control the transmitter from the computer
Coaxial built transverter for the X-Band
Alcatel BF4 (One Touch 511) information

Digital electronics

CB2 microcomputer
micro SD locker and instructions for a safe PC (Greek only)
The ATLAS computer
A single chip micro-computer for the lab

A universal variable VCO clock
Reverse linear ramp, sawtooth generator
Core rope memory
Coincident current NOR gates
Experiments on square loop toroids
A transistorized 4-bit digital computer made out of discrete DTL (in development)
A full-sized microcomputer inside a keyboard

Development of a Tele-control Home Appliance Controller (my MSc project) First pages, Main report, Schematics and datasheets
A simple, failure immune 4-bit digital computer made out of common TTL chips (in development)
The ZX-80 computer (A useable home computer built REALLY from scratch. This includes PCB etching)
The Jupiter Ace computer (A useable home computer built REALLY from scratch. This includes PCB etching. In development)
Reverse engineering of the Vectrex system (The unique vector graphics system and how to build one yourself from scratch)
The homemade PC-XT project (A greater scale PC-clone home computer. Some parts are in KIT form. In development)



Other electronics

Vibration activated LED charge pumps
High power thrifty regulator
A simple and cheap UPS
UPS for ADSL routers and embedded systems
Personal ballooning - A pioneer flying concept
Experiments for Energy Harvesting and Efficiency
A blinking LED Christmas tree
The LED Zapper game (a game for the blind or the deaf)
The SkyNet project (Low data rate laser data links, in development)

Audio electronics

My High Fidelity audio page

Audio compressor
The vacuum tube poly-synth project (VCO section)
Poor man's laboratory equipment Software I have developed (and other's useful software)
All waves RF generator
Potentiometer noise tester
3-30MHz signal generator based on the brilliant "miniVFO".
Simple MCU-free HF frequency counter
High range LED meter display
Quick components tester
HF crystal tester
Versatile oscillator/demodulator instrument (in Greek)
Ultra wideband sinusoidal VFO with AM capability
A handheld multi-purpose meter for the HF experimenter
A low profile lamp designed specifically for SMD rework
Poor man's HF spectrum analyzer
A BASIC computer designed especially for lab use (in development)
A low frequency circulator/isolator
A mini reference oscillator
A return loss bridge for impedance measurements
A mini dummy load for impedance measurements
Solid state UV PCB exposure
Semiconductor analyzer (For BJTs, mosfets and diodes. An Elektor project)
A homemade UV exposure box for big double-sided PCB fabrication
Schematix. Schematic drawing and exchanging for the radio amateur
Morse code encoder/decoder
Modified tap code encoder/decoder
DataText. Transfer data through any radio amateur text mode
The CDW communications mode (version 2)

JLab - an online electronics software suite
How to draw ARRL-style schematics
A complete software TNC for the radio amateur (other's project, documentation by me)
NBTV programs for the radio amateur (other's projects)
Mechanical work
Repairing the tuning knob of the IC-728 transceiver
Increasing the capacity of the Unimat SL (DB-200)
Making a special knob for tuning the DDS in a handheld transceiver
A depth gauge or Z-axis meter for the Unimat-SL (DB-200)
Making a special screwdriver for the lab (under development)
A table for the lathe
How to mill an enclosure on a small lathe (part of another project)
Experiments on the olive oil fuel
Useful Links  
Dc4ku website. Measurements and RF (only in German)
Great RF experiments website
S53MV website. Microwave and advanced RF projects.
JF1OZL website. Archived from
Greek Microwave Group website. Amateur group for microwave radio projects.
YO3DAC - VA3IUL website. Amateur radio projects.
LA8AK website. Amateur radio projects
SM0VPO - G4VVJ website. Amateur radio projects.
Hans Summers. Radio, Electronics and Computing Projects.
QRP and SWL homebrew equipment.
Cool homemade stuff homemade electronics components.
Digital modes experimenter website.
My professional website.
Elm Chan website. Great microcontroller projects.
Freddy Alferink website. All about accurate measurements.
Radio waves below 22KHz.
Simple QRP equipment
Homebrew electronics from Germany
Circuits from Russia
Circuits from Czech
Useful radio amateur scanned circuits
Useful ham scanned circuits
Electronics Circuits Reference Archive
HF propagation prediction data
Web SDR - Listen to DC-30MHz without an RX

Places that I have visited
A trip on a passive repeater
Rhodes island
Santorini island
Samos island
Lefkada island

Contact me (different options)
SV3ORAE-mail me
The email to contact me is:


Video call me

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Talk to me live on my transceiver
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Enter the BBS
(Located at Patras city, started on early 2019)

Two ways to connect
Dial-up: comming soon

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You are free to copy and use everything on this non-profit amateur website. Note that for copyrighted material, you may need to ask for the authors permission first. All material on this website is provided as is without any guarantee. Many of the material is my own thoughts and do not necessarily represent the truth. It is provided for you to read in order to understand the basic principles of operation. If you find your material is listed somewhere in this page and you want to remove it or get credit for it, please let me know and I will remove it immediately or add relevant notes. You may copy and use any content of this website to other pages, only if you clearly include in your pages the source that it has been taken from (which is this website). You may build and use any project only at your own risk and you are the only one that are responsible for its use. You should always consider your country regulations before building anything.

* I am paying lots each year for maintaining this website and you get that for free, please gain knowledge from what you find here and be reasonable about copyright stuff anyway. Contact me FIRST before you make any nasty post anywhere on the web about my website!

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