Intermediate Course23/08/2014

This week..

• Introduction to Intermediate Course• Safety• Soldering• Construction of Simple DC Circuit

Introduction to Intermediate Course

Week 1 Week 2 Week 3 Week 4 Club Night Week 5 Week 6 Week 7 Exam

Session 1 Session 2 Session 3 Session 4 Session 5 Session 6 Session 7 Session 8Exam & Revision

23/08/2014 30/08/2014 06/09/2014 13/09/2014 16/09/2014 20/09/2014 27/09/2014 04/10/2014 TBC

Hour 1 (Theory)Intro, Safety,

SolderingTechnical Basics / Components pt

1Technical Basics / Components pt2 Recievers Measurements

Operating Practice EMC, Propagation

Antennas and Feeders

30minutes revision

Hour 2 (Practical Items) Simple DC Circuit Measure resistors Diode and Transistor Transmitters 13A plug / PL259 Project VFO revision Exam

Introduction to Intermediate Course

• 50 Watts of Power – but note there are exceptions!

• Microwave Frequencies: 1.3GHz (23cms) - 250GHz

• Unattended Operation

• Fast Scan TV

• Build your own Transmitters

• Some remote control

Introduction to Intermediate Course

• Intermediate has more frequencies.

• Note the exceptions on power limits, and geography

• Some are ERP limited freqs

• Not all are 50W

• Provided in the exam, remember to use it.

Safety

• Soldering• Use of hand tools• Working at heights• Electricity• RF

Safety

• Soldering

Keep soldering iron in stand to avoid contact with skin when not in use.

Make sure soldering is done in well ventilated areas. Avoid breathing infumes as they can cause breathing problems particularly to asthmatics.

Eye protection MUST be worn to avoid solder splashing into your eyes.

Safety

• Use of hand tools.

Work in tidy area, away from body to avoid injury.

Handle tools with care. They can cut face or hands if used incorrectly.

Secure any items if you are to saw, drill or file them. Items can spin when drilled orslip/move while being worked on which can cause injury.

When using a drill ensure the chuck key is removed before using it, else it may fly off!

Safety

• Use of hand tools. Cont…

When drilling protective eye wear MUST be worn to avoid swarf from hitting your eyes.

Use a centre punch when drilling to help prevent the drill slipping when making the hole.

Bench mounted drills are safer to use than hand drills due to them, allows you to keepHands well away from danger area. Also gives more control. (Still need to wear eyewearAnd remove chuck).

Safety

• Working at heights

When working from ladders you MUST have a ratio of 1:4. Example. Ladder in image is 1m away from the wall and 4m high.

Make sure when using a ladder that it is;1. Secured at the top or held by an adult at the bottom to avoid slipping2. Do not over reach, you don’t want to fall off.3. Hard hats should be worn when working at height or around others working at height4. If you are going to need tools while working at height its best to wear a tool belt or another tool carrying device. Also prevents objects falling.

Safety

• ElectricityTake note of overhead cables when using ladders and putting up antennas. Eithercan either cause arcing or come into contact with cables and will result in a dangerous shock

Use the correct fuse. Remember Current = Power / Volts, where Volts is 230v. Example 120watt PSU – 120/230 = 0.5 Amps

Residual Current Devices (RCD) gives you better protection then just using conventional fuses.RCDs will detect currents to earth of about 30mA where as a fuse will only blow at several ampsAnd only when there is a short circuit. (Live to Neutral or Live to Earth)

Remember if you are to work on equipment which has large or high voltage capacitors you need to dischargeThem first, as they can store dangerous electric charges.

Safety

• RF

The main health effect of exposure to electromagnetic radiation is heating of body tissue.

Guidance on safe levels of RF radiation is available from government and international bodies (HPA – Health Protection Agency and ICNIRP- International Committee on Non-Ionising Radiation Protection)

DO NOT look down a microwave frequency waveguide or to stand close to or in front of high-gain antennas as they may be in use. Your eyes are vulnerable to heating. The focus of the waveguideOf a microwave enhances the heating effect to a smaller area of the body.

Soldering• What is soldering?

Soldering is a method of joining metal wires and components using a hot soldering iron to melt the solder

Solder contains flux which is to help the solder flow and to prevent a layerOf oxide forming on the areas being joined.

Not all metals are easy to solder. Tin, copper, and brass solder well, whereAs aluminium and stainless steel require special techniques. This usually willNot be a problem when building circuits or soldering PL259s for example.

You should always keep the soldering iron tip clean. This is to remove oxide.To prevent oxide and to help the heat conduction, the iron tip should be“tinned”. This is why you should tin wires before soldering them onto connections.

SolderingWhen making solder joints they should be made reasonable quickly to avoid damage to components. Leaving the iron on the joint too long can cause “cold/dry” solder joints.

• Construction of Simple DC Circuit

Materials and Components

• Block of wood 10cm by 10cm• Small bulb holder• Bulb• Resistor (R1) 2.2ohm – Red Red Gold• Resistor (R2) 470ohm – Yellow Violet Brown• Drawing pins x 5• AA battery holder• Single Core wire (around 20cm)

SEE PAGE 8 in your book.

• Construction of Simple DC CircuitLayout

Push into the board the pinsIn the layout shown.

• Construction of Simple DC CircuitSolder R1 and R2Place Bulb holder on board

• Construction of Simple DC CircuitLayout

Solder into place the four wires

Notice the wire in the bottom rightIs only solder to one pin.

• Construction of Simple DC CircuitLayout

Solder on the Positive (+) andNegative (-) wires from the batteryholder

• Construction of Simple DC CircuitLayout

Put Batteries into holder and putBulb into holder

• Construction of Simple DC CircuitLayout

Touch wire to pin to create the circuit

• Construction of Simple DC CircuitLayout

Make sure you put your name on theBoard.

Also label up the board.

PaulM0PFX

A

B

CD

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•Next Week

Technical Basics and Components Part 1

Measuring Resistors..