Revision 10, July 2006

A Guide to Building an Amateur Radio Station

By Frank W. Harris, KØIYE

Copyright © Frank W. Harris, 2002, 2004, 2006



NOTE: There is a Spanish translation of this book here: http://www.ea2ry.com/libroradio/.

REQUIRES ADOBE ACROBAT READER.

Table of Contents:

FOREWORD





Chapter 1

THE FASCINATION OF RADIO

Exploring the shortwave bands

Growing up in the Morse code era

The joy of building it yourself

A brief history of radio communication

Henry, Maxwell, Hertz, Tesla and Marconi.

Fessenden, Edison, Flemming, DeForest and Armstrong

The sinking of the RMS Republic and the birth of ham radio

Ham radio in the last 80 years

Becoming a radio amateur

Chapter 2 HOMEBUILDING AMATEUR RADIO EQUIPMENT

What qualifies as homebuilding?

When homebrewing is not appropriate

Barriers to modern homebuilding

Time, frequency stability and lead inductance

Basic electrical knowledge

Magnets & static electricity

Voltage, current, resistance, energy and power

(Illustrated with drawings of water & mechanical analogies)

Conductors, Insulators and semiconductors

Capacitors, inductors, transformers & alternators

Home power distribution, transformers at low and high frequencies

Chapter 3 SETTING UP AN ELECTRONICS WORKSHOP

R&D as recreation

How to build radios (or anything else) in your basement

Persistence, read books, keep a notebook, & work in small increments

Minimum tools needed

The ARRL Amateur Radio Handbook

Soldering irons and small tools

Drills & thread taps

Wood carving gouges for making PC boards

>50 MHz Oscilloscope

Frequency counter

Quality multimeter

Lab power supply

Calculator

Lab notebook

Collection of electronic junk

Parts catalogs

Capacitance meter

Test leads & socket boards

Nice-to-have tools

RF & audio generators, spice software & spectrum analyzer

Chapter 4 HERTZIAN WAVES IN THE BASEMENT

The nature of radio waves

Mechanical and LC electrical oscillators

Antenna and transmission line theory

Crystal set components

LC tuner

PN junction diode detectors

P-type and N-type semiconductors

Detection of AM signals

Homebuilding the parts for a crystal set

The Jamestown diode

The Caribou headphone

Revisiting Crystal Sets in 2006

Learning to troubleshoot

Selective tuning

Recreating Hertzs radio equipment

Transmitting and receiving as simply as possible

The 1880 ten-meter communicator

Proving that radio waves exist and arent just capacitive or magnetic coupling

Demonstrating standing waves to measure frequency

Building homebrew transistors

Bipolar transistors, PNP and NPN

Demonstrating voltage gain

The Boulder Rock Radio

Chapter 5 GETTING ON THE AIR - DECIDING WHAT TO DO FIRST

How to earn a license

The rules of the homebuilding game Whatever makes you happy!

Picking an HF band

Getting acquainted with the HF ham bands, 160 10 meters

Instant high quality HF communications

VHF/ UHF handheld transceivers

Building an antenna

Dipoles, regular and folded

Multi-band dipoles

80 meters when you dont have room for a dipole

The curtain rod vertical

A multi-band vertical antenna

Lightning protection

Chapter 6

BUILDING A QRP HOMEBREW

A single-band, crystal-controlled, QRP module

The transmitter mainframe

HF construction methods

Making your own PC boards

"Dead Bug" and "Gouged Board" construction

Superglue "Island Boards"

Coax jumpers

Shielded boxes

The complete QRP crystal-controlled transmitter

Transistor amplifiers and oscillators

How an amplifier becomes an oscillator

Class A and Class C amplifiers

Stabilizing the operating point, bypass caps and emitter resistors

Quartz crystals the key to frequency stability

The 40 meter QRP circuit

Oscillator and buffer

Inductors, RF transformers and impedance matching

Tapped toroid inductors

How to wind them (and mistakes you might make)

The final amplifier stages for the QRP

Tuned versus broadband - Use both for best results

Bifilar wound, broadband transformers

How to wind them (and how you might screw up)

Ferrite bead RF chokes, expensive RF power transistors, heat sinks & output connectors

Conquering inductors

Calculating resonance

Calibrating trimmer capacitors

Calculating turns on powdered iron and ferrite toroids

Chebyshev output low pass filters

Keying your QRP

MOSFET power transistors

A "spot switch" for the QRP

Chapter 7

BUILDING A CODE PRACTICE RECEIVER

A simple, direct-conversion receiver

A great first project for a new ham

Excellent sensitivity and good stability

Poor selectivity

Adding 700 Hz audio filtering

High pass and low pass filters

Cascaded bandpass filters increase selectivity

Operational amplifiers

Building with integrated circuits

AM broadcast filter

Getting rid of the image

Chapter 8 POWER SUPPLIES

Line powered power supplies

Power supply safety features

Isolation, 3-conductor cords, fuses, switches, ratings

Supply performance and regulation

Rectification, ripple, chokes, capacitors, & bleeders

Zeners, linear regulators, switching regulators

A QRP regulated power supply

A battery power supply for the radio shack

Solar cell charging, low drop-out regulators

Battery powered shack lighting

Chapter 9 ACCESSORIES FOR THE TRANSMITTER

A straight key

An electronic bug

Building dummy loads

"T" type antenna coupler

A low pass filter

How to stay legal with a homebrew transmitter

Antenna and power relays

Homebrew QSL cards

Chapter 10 VARIABLE FREQUENCY OSCILLATORS

Drift is a big deal today

Low frequency VFOs drift less than high frequency VFOs

JFET transistors

The oscillator circuit

The buffer, final amplifier and output filter

The 50 secrets of avoiding drift

JFETs, single-side PC boards, cast metal box, multiple NPO caps, small variable caps, precision voltage regulation and more

Vernier tuning

Varactor tuning elements advantages and disadvantages

A precision power supply

A voltage doubler power supply for battery use

Square wave generator with a multivibrator

Squaring up the square wave

Charge pump, diode/ capacitor voltage doubler

Schottky diodes for efficiency

Temperature compensation methods

Positive coefficient capacitive trimmer compensation

How to adjust the compensator

Thermistor/ varactor temperature compensation

Chapter 11

Building a VFO for the higher bands (PMOs)

Old approaches that no longer work

Frequency multiplication

High frequency oscillators

PreMix Oscillator method of frequency translation

A VFO-controlled QRP module

Crystal oscillators are stable, arent they?

Crystal oscillator circuits

Butler oscillators and big crystals

Mixers, bipolar transistor and dual-gate MOSFET

Optimum drive requirements

Direction of tuning, drift error cancellation

Multistage filters and filter/amplifiers

The QRP final amplifier stages

Chapter 12 FINAL AMPLIFIERS

The basic features of a modern linear power amplifier

It looked easier in the Handbook

Linear "noise mode" operation

A tuned 50 watt class B amplifier

Ferrite balun transformers

An untuned, sort-of-linear, class B, amplifier

Keying the 50 watt transmitter

A linear Class AB amplifier, this time for sure

Single Sideband (SSB) needs a linear

Biasing without thermal runaway

Clamp diodes prevent runaway

Mechanical construction

Chapter 13 BUILDING A HOMEBREW HF RECEIVER

Building a receiver - an unusual adventure

Whats a reasonable goal?

An "adequate performance" HF communication receiver

Does it have to be so complicated?

Planning your receiver

Direct conversion versus superhetrodyne

Why not single conversion?

Start with a single-band, single-conversion superhetrodyne

How do modern digital receivers do it?

Receiver construction build with shielded modules connected by thin coax.

The 80 meter preselector

Reception on 80 meter and 160 meters is aided by a tuned transmatch

The Variable Frequency Oscillator

Mixer magic

Mixers will give you lots of static and howls and squeals

A practical homebrew mixer made from discrete parts its harder than it looks

Dual gate MOSFET mixers

Not all MOSFETS work equally well

Crystal ladder filters essential for CW

All 9.000 MHz crystals arent equal

Using the BFO oscillator to match crystals

Switch in filters with a rotary switch

The IF amplifier

Lessons learned from a dual-gate IF amplifier

The cascode amplifier strip - variable gain with constant Q

Automatic Gain Control (AGC) - not a luxury

The product detector

Nearly anything works at least a little

The AF amplifier a vital part of the signal dynamic range

Protecting your ears from strong signals

How Hi-Fi should it be?

Driving a speaker

HF converters for the other ham bands

Crystal oscillators

Bandswitching

Receiver power supplies

Use a linear regulator, not a switching regulator

Chapter 14 OLD-TECH VACUUM TUBE RADIO

How old can radio technology be and still be used on the air today?

Why bother with vacuum tubes?

Glowing filaments, colored plasmas & Jules Verne glass envelopes

Power supplies for tubes

High voltage power supply safety

The old-tech QRP transmitter

Vacuum tube amplifiers

The three roles of the triode filament

RF sinewave oscillator

Quartz crystals

Triode and pentode oscillators

Old-tech voltage regulation big, crude, expensive, but beautiful

The travails of triode tubes

The oscillator and buffer

The final amplifier triodes chirp

The transmitter power supply

An inadequate supply from a 1935 radio

A good power supply made from cheap, modern, boring parts

How to check out junk power transformers

A complex but adequate supply made from ancient parts

It works! No one suspects its old and its a success on todays 40 meter band

An old-tech receiver

A super regenerative receiver made from ancient tubes

The power supply

Super-regen on the modern hambands

Lots of fun, but not up to modern QRM & QRPs - back to the drawing board!

Chapter 15 THE NOBEL PRIZE FOR SIDEBAND

It cant be that hard! Want to bet?

The sideband generator how it works

The 9 MHz oscillator / amplifier

The audio amplifier

The balanced modulator

Building your own crystal ladder filter

Decoupling the power supply leads

Getting rid of RF feedback - RF filtering for all inputs

Tuning and testing

Using the generator for AM modulation and CW

Moving the 9 MHz SSB signal to a hamband

Move the SSB only once!

No wonder most ham rigs are tranceivers

Moving the 9 MHz signal to the difficult HF hambands

Move the VFO first, then mix it with the SSB 9 MHz.

mix it with the SSB 9 MHz. Pick your oscillator and VFO frequencies carefully

Hearing your own VFO in the receiver

The hardest band 17 meters

Covering the widest band 10 meters

A linear sideband QRP, VFO-tuned module

All stages must be linear and low distortion

All gain stages should be broadband to prevent oscillation

Sometimes high pass filter output is needed & not the usual low pass

Checking out the generator

Driving a 50 watt linear amplifier

Chapter 16 ANCIENT MODULATION

Defining amplitude modulation

Modulating vacuum tube final amplifiers

Plate, screen & cathode modulation

A "collector modulator"

Converting a MOSFET keyer into a modulator

Generating AM with an SSB balanced modulator

Compensating for non-linearity

Compression by accident

You probably don't need to build a compressor

Ham TV - The old way

Fun with an ancient flying spot scanner TV camera

In conclusion:

Homebrew ham radio is never complete - when it works perfectly and does all the latest stuff, the hobby is over. Not likely. Long live homebuilding!

Thanks for reading my book.

73's Frank W. Harris, KØIYE