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Presentation on theme: "AMATEUR RADIO TRAINING"— Presentation transcript:

Transmitters & Receivers v1.11 ©

2 Transmitters & RECEIVERs
Block Diagrams Modulation Types Station Setup

3 Transmitter Basics A radio transmitter has four basic stages:
Audio Stage Gets signals from the microphone Frequency Generator Creates the radio signal on the right frequency Modulator Mixes the radio and audio signals together RF Power Amplifier Increases the combined signal and feeds to the antenna

4 Transmitter Block Diagram
1 2 4 3 1: Audio Stage 2: Modulator (More on this shortly) 3: Frequency Generator (also referred to as an Oscillator) 4: RF Power Amplifier

5 Receiver Basics A radio receiver has three basic stages:
Tuning / RF Amplifier Tunes into the required frequency Amplifies the weak signal so that it can be used Detector Extracts the audio from the radio signal. Often called “demodulation” There are different types of detector for each modulation type Audio Amplifier Amplifies the audio and feeds it to a loudspeaker

6 Receiver Block Diagram
1 2 3 1: Tuning and RF Amplifier 2: Detector (Also referred to as a “De-modulator”) 3: Audio Amplifier

7 Amplitude Modulation (AM)
Audio Signal Carrier Modulated signal

8 AM Transmitter Block Diagram
Modulator Audio Stage RF Power Amp Frequency Generator

9 Frequency Modulation (FM)
Audio Signal Carrier Modulated signal

10 FM Receiver Block Diagram
Tuning & RF amp Detector Audio Amplifier

11 AM vs FM Audio Signal AM Signal FM Signal

12 Transmitting At Foundation-level, only commercially-purchased transmitters can be used (no construction) You must only transmit on allocated frequencies and at permitted power levels ‘Over-modulating’ or ‘Over-deviating’ may result in interference to other channels as well as poor audio quality. Take care with audio levels (microphone gain and shouting) You must stay in-band, not cause interference, and test transmitters “from time to time”.

13 Station Setup Microphone Power Supply
Transceiver (transmitter & receiver) SWR Meter RF Filter ATU Antenna

14 Summary Block Diagrams Modulation Types Station Setup
Remember the diagrams for transmitters and receivers Modulation Types Amplitude Modulation Frequency Modulation Station Setup Setting up a station correctly is one of the Foundation practicals

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