AMATEUR RADIO

What electronics tutorials on line help is available to become a licensed Amateur Radio Operator?
This site offers some very useful and particularly comprehensive electronics tutorials to help you on your way toward becoming an amateur radio operator. Please feel free to fully explore our site.
Of course many of these electronics tutorials are applicable to experienced constructors as well as advanced electronics students looking for electronics tutorials.
Many other sites also cater for people seeking to become amateur radio operators and conduct electronics tutorials.
Just what is Amateur Radio?
The amateur radio fraternity comprises hundreds of thousands of people world wide who share a very broad common interest. Amateur radio operators come from very diverse backgrounds and age groups. Ranging from adolescents to senior citizens, boys and girls, men and women - amateur radio operators include doctors, bus drivers, vetinary surgeons, painters, engineers, homemakers, university professors, students, politicians, labourers, lawyers and the retired as well as the unemployed, there are no limits to backgrounds.
Somewhere in this wide world there are people with similar interests and backgrounds to yourself who also just happen to be amateur radio operators.
Amateur radio operators are entitled to communicate with one another world wide in accordance with the level of licensing the amateur radio operator has achieved.
What does Amateur Radio Operating entitle me to?
Depending upon your level of licensing for your particular country you might communicate by television, digital communication in conjunction with your computer, by satellite, by traditional high or very high frequency communication using FM, single sideband or more demanding, by morse code. The choice is yours. It depends on your area of interest as an amateur radio operator.
What do I need to do to become a licensed Amateur Radio Operator?
Find out the licensing requirements for amateur radio operators at your location, in particular establish the provisions for sitting for examinations to become an amateur radio operator. Next find out if there are any amateur radio clubs in your locality - the amateur radio operators at these clubs will offer you no end of help provided you approach them in a sensible way. All amateur radio operators remember when they first needed the same help you are now asking for but, remember self help comes first.
Demonstate to your new amateur radio operator friends that you are prepared to put in a bit of work on your own behalf and mainly you need advice, tuition and guidance to pass your exams. Above all else be polite.
Good amateur radio operators are always polite.
Good Luck and please do join us - you will be glad you did - it's real fun.
Ham Radio education
Anyone starting out in ham radio needs a copy of the ham radio bible. It's called "The ARRL Handbook for Radio Amateurs - 2003.
The latest is the 80th edition. It is not called the "electronics bible" for nothing. I have several editions as far back as 1943.
The mammoth 1216 pages translate theory into practice through the large variety of hands-on-projects packed into THE ARRL HANDBOOK. From Antennas to Zener diodes, Transceivers to Switching Power Supplies, HF and VHF Propagation to Power Amplifiers—it’s covered in this edition. Among the newest material is a chapter on digital signal processing, a remote-controlled automatic antenna switch and computer hardware.

OSCILLATORS

THIS OSCILLATORS TUTORIALS SITE
This section devoted to oscillators is one of the most interesting for newcomers. You need a thorough grasp of oscillators to fully understand the later and much more complicated electronics tutorials on radio receivers and transmitters.
OSCILLATOR BASICS
Here we explain a lot of the basics involved. We discuss the principles of oscillator operation, briefly look at two popular types, Hartley Oscillators and Colpitts Oscillators as well as Frequency or Phase Stability of an oscillator. Then we go on and consider reducing Phase Noise in oscillators, discuss the effects of ambient changes on stability in oscillators and finally minimizing frequency drift in oscillators.
CLAPP OSCILLATORS
A clapp oscillator is in effect a series tuned version of the colpitts oscillator. Perhaps the simplest Colpitts oscillator to construct and get running is the "series tuned" version, more often referred to as the "Clapp Oscillator". Because there is no load on the inductor a high "Q" circuit results with a high L/C ratio and of course much less circulating current. This aids drift reduction. Because larger inductances are required, stray inductances do not have as much impact as perhaps in other circuits.
COLPITTS OSCILLATORS
Colpitts oscillators are somewhat similar to the shunt fed Hartley circuit except the Colpitts oscillator, instead of having a tapped inductor, utilises two series capacitors in its LC circuit. With the Colpitts oscillator the connection between these two capacitors is used as the centre tap for the circuit.
CRYSTAL OSCILLATORS AND CRYSTAL GRINDING
Crystal oscillators are oscillators where the primary frequency determining element is a quartz crystal. Because of the inherent characteristics of the quartz crystal the crystal oscillator may be held to extreme accuracy of frequency stability. Temperature compensation may be applied to crystal oscillators to improve thermal stability of the crystal oscillator.
What is crystal grinding? There was an exchange of emails asking about crystal grinding on the 'Flying Pigs' list. Karl Kanalz, W8TIF gave his insight and experience on the topic of crystal grinding FT-243 crystal blanks and has graciously consented to it being reprinted here.
HARTLEY OSCILLATORS
Hartley oscillator are inductively coupled, variable frequency oscillators where the oscillator may be series or shunt fed. Hartley oscillators have the advantage of having one centre tapped inductor and one tuning capacitor. This arrangement simplifies the construction of a Hartley oscillator circuit.
VOLTAGE CONTROLLED OSCILLATORS
A voltage controlled oscillator or as more commonly known, a vco, is an oscillator where the principal variable or tuning element is a varactor diode. The voltage controlled oscillator is tuned across its band by a "clean" dc voltage applied to the varactor diode to vary the net capacitance applied to the tuned circuit.
OSCILLATOR DRIFT AND DRIFT CORRECTION CIRCUITS
Oscillator drift can be related directly to frequency stability. Drift is the unwanted and unwarrented change in frequency measured over seconds, minutes or hours. Just how stable should an oscillator be? Your oscillator or any electronic project should be as state-of-the-art as is possible, consistent with your design goals.
An oscillator drift correction circuit is any circuit which automatically brings an oscillator back onto it's assigned or tuned frequency. Such circuits might be frequency synthesisers with phase locked loops, automatic fine tuning circuitry AFT or, AFC in AM Receivers and automatic temperature compensation built into an oscillator circuit.

Ohm's Law Tutorial

The voltmeter is connected across the resistor, to measure the voltage across the resistor. The ammeter is connected in series with the resistor, to measure the current flowing around the circuit and through the resistor.
Mr Ohm discovered that if you double the voltage across the resistor then the current through it doubles. If you halve the voltage then the current is halved. This means that the current is PROPORTIONAL to the voltage.
He also found that if you double the value of the resistor then the current through it is halved. If the value of the resistor is halved the the current is doubled. Thus the current is INVERSELY PROPORTIONAL to the resistance.

To use the VIR triangle place your finger over the value you wish to find. If you wish to find V then multiply I by R If you wish to find I then divide V by R.

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