Midland Amateur Radio Club Inc. - Reg. No. A0018595R
Training
The next Foundation Licence Training/Assessment Weekend is scheduled for September 20th and 21st.
If you are interested in becoming an Amateur Radio Operator, you can download the Licence Training and Assessment Information and Application document.
The Club actively promotes entry to the ranks of amateur radio operators and provides a comprehensive training package to assist future candidates.
The Wireless Institute of Australia (WIA) is responsible for conducting licensing examinations in Australia assisted by formerly accredited/appointed local amateurs. Accredited Club members are:
Name
Callsign
Position
Ross Pittard
VK3FCE
Assessor
Ian Gillard
VK3ZZG
Assessor
Kevin Crockett
VK3CKC
Learning Organiser
Nick Angelo
VK3UCK
Learning Facilitator
The Club conducts training courses on an as required basis at the Club rooms in Vine Street, Bendigo.
Soldering Class - On March 15th, 2008, the Club conducted a soldering class. It was a simple class with a lot of productivity crammed in. If you're looking for a high-value class, this is how it was done.
Unlike many years ago, new entrants into the hobby of amateur radio predominantly do not enter the hobby via an interest in electronics. The Australian Foundation Licence does not require other than a quite superficial knowledge of the world of electronics. Requests for some tuition in soldering led to this particular class which endeavoured to provide as much instruction as possible within the time available.
The construction project was a simple, digital, crystal oscillator using crystals from the junk box and a purpose-designed circuit board. All parts were provided in a simple kit. A number of spin-off or peripheral subjects were also covered to a greater or lesser degree as activities other than the actual oscillator construction would eventually lead to them.
1. Adjustable Power Supplies - Discussion on the need for adjustable power supplies having both voltage and current limiting and how to adjust them for expected/required conditions in using them for experimental purposes and testing projects.
The power supply pictured here is a multi-purpose supply that can be two individual and independent supplies, connected in series to form a balanced (+, 0, -)supply or connected in parallel to double its output current.
2. Oscilloscopes - Covered a general operation of an oscilloscope. This included setting the timebase, sensitivity and interpreting the display.
The oscilloscope pictured here is a Protek 6510, 100MHz, dual trace.
3. Multimeters - Covered the difference between analogue and digital multimeters and the circumstance in which you would use either one in preference to the other. This was followed by selecting the input configuration for measuring a variety of elements, setting the measuring range and interpreting displayed results. Students were warned against setting a multimeter for measuring current and then connecting it across a supply. This will blow the fuse in the instrument.
The digital meter on the left is a Digitech QM1535 available from Jaycar for around $AUD30.00. The analogue meter in the centre is a Hung Chang HC-505E available from WES Components for under $AUD70.00. Finally, the digital meter on the right is a Fluke 73 - a few years old but purchased new from a recent hamfest for $AUD75.00.
4. Simple introduction to Digital Electronics - A brief discussion on input/output states of a number of basic logic gates. This included the ability to determine output states from known input states and vice versa. This was followed by operating voltages required by the various logic families.
5. Crystal-controlled oscillators - A brief description of what an oscillator is and the general roles oscillators play in the generation and control of frequencies used in transmitters and receivers. A comparison between crystal oscillators and their tuneable LC counterparts followed. Finally a discussion of when crystal oscillators might be required in projects.
This image shows a completed crystal oscillator constructed at the soldering class.
6. Component Identification - This section covered the recognition of the components in the construction project including various resistors and capacitors, IC, crystal and the required operating supply voltage. The difference between the number of bands on resistors and the multiplicity of capacitor markings were also covered.
7. Hand Soldering process and Practices - This section described the makeup of solder, differences between soldering irons and bits and their suitability or otherwise for electronics. This was followed by what happens during the soldering process and what needs to be achieved, soldering flux and paste and the steps involved in soldering. Finally work inspection and how to recognised poor soldered joints.
8. Construction of a crystal-controlled oscillator - The circuit is quite simple, consisting of:
1 x 74LS00 Quad 2-input NAND gate, 2 x 330 ohm resistors, 1 x 100n capacitor, 1 x 120pF capacitor and 1 HF crystal as required. The crystal used in this class was marked as 4.194304MHz.
The circuit is shown here. The crystal is shown as a nominal 4.0MHz. The circuit, however, has been tested to 20.0MHz without any problems.
9. Checking/Confirming Workmanship - This section of the class covered checking accurate placement of individual components and checking each soldered joint for quality/integrity and unwanted solder bridges or shorts.
10. Testing/Proving oscillator operation - Each student had the opportunity of having their oscillator connected to an appropriately adjusted power supply to see how it would react. All but two worked as expected first off. The two that didn't required adjustment to a couple of soldered joints and they were then operational.
The next step involved connecting the circuit to an oscilloscope to view the output waveform.
A frequency counter was then used to display the working frequency.
Finally, the radiated signal was tuned in on a receiver where the effect of hand capacitance on the circuit board demonstrated how the frequency changed slightly. The presence of harmonics was also verified by listening to multiples of the indicated frequency.
11. Effect of changing the crystal - Finally, another oscillator was made with identical components except for a considerably lower frequency crystal to demonstrate that the crystal frequency was the main frequency determining factor.
This image shows parts placement, various calculations/explanations and a list of individual frequencies that were measured.
Summary - This class showed that it is quite easy to provide a simple training course and deliver a lot of value in a relatively short time. Providing a constructed item that students can take home with them for some personal observation and experimentation provided an added level of incentive and involvement. All in all, a very successful undertaking.
Please contact the Midland Amateur Radio Club if you wish to know more or would like to attend a similar class in future.
Created 2005 by
Kevin Crockett. Comments and suggestions may be e-mailed to
Soldering Class - On March 15th, 2008, the Club conducted a soldering class. It was a simple class with a lot of productivity crammed in. If you're looking for a high-value class, this is how it was done.
1. Adjustable Power Supplies - Discussion on the need for adjustable power supplies having both voltage and current limiting and how to adjust them for expected/required conditions in using them for experimental purposes and testing projects.
2. Oscilloscopes - Covered a general operation of an oscilloscope. This included setting the timebase, sensitivity and interpreting the display.
3. Multimeters - Covered the difference between analogue and digital multimeters and the circumstance in which you would use either one in preference to the other. This was followed by selecting the input configuration for measuring a variety of elements, setting the measuring range and interpreting displayed results. Students were warned against setting a multimeter for measuring current and then connecting it across a supply. This will blow the fuse in the instrument.
5. Crystal-controlled oscillators - A brief description of what an oscillator is and the general roles oscillators play in the generation and control of frequencies used in transmitters and receivers. A comparison between crystal oscillators and their tuneable LC counterparts followed. Finally a discussion of when crystal oscillators might be required in projects.
8. Construction of a crystal-controlled oscillator - The circuit is quite simple, consisting of:
1 x 74LS00 Quad 2-input NAND gate, 2 x 330 ohm resistors, 1 x 100n capacitor, 1 x 120pF capacitor and 1 HF crystal as required. The crystal used in this class was marked as 4.194304MHz.
10. Testing/Proving oscillator operation - Each student had the opportunity of having their oscillator connected to an appropriately adjusted power supply to see how it would react. All but two worked as expected first off. The two that didn't required adjustment to a couple of soldered joints and they were then operational.
A frequency counter was then used to display the working frequency.
11. Effect of changing the crystal - Finally, another oscillator was made with identical components except for a considerably lower frequency crystal to demonstrate that the crystal frequency was the main frequency determining factor.
Summary - This class showed that it is quite easy to provide a simple training course and deliver a lot of value in a relatively short time. Providing a constructed item that students can take home with them for some personal observation and experimentation provided an added level of incentive and involvement. All in all, a very successful undertaking.