AM-FM Radio

1
AM-FM Radio

• Superhet 108

2
Superheterodyne Principle

• The superheterodyne principle was originally
  conceived in 1918 by Edwin Armstrong during WWI,
• The concept was to overcome the deficiencies of
  Vacuum tube technology,

3
Heterodyning

• If a radio station were transmitting on 300 kHz
  and the oscillator were set to 400 kHz, as well
  as the original 300 kHz, the same station would
  be also heard on 100 kHz and 700 kHz.
• Mixing two frequencies creates two new
  frequencies,
• one at the sum of the two frequencies mixed
  (700),
• and the other at their difference (100).
• This is known as heterodyning.

4
Assembly of the AM Radio

• Assembly of the AM-FM Radio is broken down into 9
  sections,
• Section 1- Audio Amplifier,
• Section 2- AM Detector and Automatic Gain Control
  (AGC) Stage,
• Section 3- Second AM IF Amplifier,
• Section 4- First AM IF Amplifier,
• Section 5- AM Mixer, AM Oscillator, and AM
  Antenna,

5
Assembly of the FM Radio

• Section 6- The FM Radio,
• Section 7- Second FM IF Amplifier,
• Section 8- First FM IF Amplifier,
• Section 9- FM RF Amplifier, Mixer,
  Oscillator, and Automatic Frequency Control
  (AFC),

6
Testing

• After assembling each section, you will test that
  section following the directions in the book,
• Record all voltages, amperages, etc in your book,
  and on the Design Brief that is associated with
  that section,
• Static Measurements (voltage, amperage) will be
  done with a Multimeter,
• If your project fails that section test, then
  check each and every part that you installed and
  soldered,
• Do not move to the next section until the radio
  passes testing for each section,

7
Soldering

• Read page 4 in the instruction manual,
• Soldering is VERY important, follow the correct
  procedures explained and shown on page 4,
• Excessive solder, Solder bridges, insufficient
  solder, or insufficient heat will cause a poor
  connection and keep your radio from functioning
  correctly,

8
Component Parts

• As you install the component parts, resistors,
  capacitors, test points, transistors, etc.) make
  sure you read each to insure that it is the
  correct component,
• Check off each in your instruction book as you
  place it on the circuit board,
• Pay attention to polarity of all the component
  parts, positive to positive, negative to negative,

9
Design Briefs

• The design briefs for this project are broken
  down by section,
• While working on the radio project, additional
  design briefs for related material are to be
  completed,
• As you complete each section, record your testing
  results in the instruction manual, and on the
  associated design brief. Then upload the design
  brief to the instructor via the classroom
  website,
• The final design brief is a custom stand to
  display your completed radio,

10
Radio Assignment 1

• Visit the following URL http//www.antiqueradios.c
  om/superhet/
• Using the information found at this website (and
  others) create a PowerPoint that details the
  development of the superheterodyne radio,

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Radio Assignment 1

• The PowerPoint must
• Include detailed information on the development
  of the superheterodyne,
• Include graphics/pictures,
• Include a bibliography page,
• Be at least 25 slides in length,
• Use 10-12 point type,
• Be saved in a webpage format,
• Not include sound,
• Be original material, (no cut and paste, except
  for pictures),
• Be completed on or before January 29th , 2016.

12
Today

• Begin work on Radio Assignment 1,
• Watch the video History of Radio Marconi,
• Video is available on the classroom website
  dashboard, click on the Research Topics button,
• Complete the video worksheet,