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Welcome

Welcome. Telecommunications Telegraphy Radio Antennas. Who we are. Dr. David Conn (VE3KL) Dr. Ken Pulfer (VE3PU) Bryan Rawlings (VE3QN) And, we are all Radio Amateurs. Imagine. It’s 1840, you are in Ottawa and you want to send a message to a friend in Montréal … No telephone

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Welcome

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  1. Welcome Telecommunications Telegraphy Radio Antennas

  2. Who we are ... • Dr. David Conn (VE3KL) • Dr. Ken Pulfer (VE3PU) • Bryan Rawlings (VE3QN) • And, we are all Radio Amateurs

  3. Imagine • It’s 1840, you are in Ottawa and you want to send a message to a friend in Montréal … • No telephone • No cellphones • No Internet • No Facebook or Twitter

  4. “Instant Messaging” – 1840 version • write your friend a message • with pen and paper • take it to the Post Office • carried to Montréal by horse and carriage • arrives a few days later • reply comes back the same way

  5. The electric telegraph !! Then, A Marvellous Invention

  6. The Morse Code

  7. Next, Wireless !! Guglielimo Marconi Heinrich Hertz James Clark Maxwell

  8. This is a diagram of an old spark-gap radio transmitter … How They Did It …

  9. Early Radio was weird !

  10. Radio Waves – the long and the short wavelength

  11. Do you know what a Hertz is? • No! It’s not a rental car! • not today, anyway • It’s the unit of frequency • one Hertz = one cycle-per-second • It’s named after Heinrich Hertz, the scientist who first demonstrated radio waves

  12. Frequencies and Wavelengths • Frequency and wavelengths go together • Like soap and water (or whatever) • “low” frequency > long wavelength • CFRA: 580 kiloHertz – 500 metres • “high” frequency > short wavelength • Magic-100 : 100.3 MegaHertz – 3 metres • Hint: divide speed of light by frequency to get wavelength

  13. The Antenna … makes it happen !

  14. Keep It Simple- the dipole The simplest antenna is called a “dipole”. It is one-half wavelength long and connected to the transmitter/receiver at its center.

  15. This big antenna – about 125 metres high – is used to transmit radio waves at a frequency of 650 kiloHertz. It is used by AM radio station WSM in Nashville TN. A part of the antenna is in the ground. The Antenna

  16. Will that be horizontal or vertical?

  17. You will see lots of these ! These are the antennas at cellular radio sites. Which way are they polarized?

  18. Not many of these anymore ! This is an off-the-air television antenna.

  19. Directional Antennas These radio waves go to the left

  20. This is an antenna, too Do you know where the “antenna” is?

  21. The elements of this antenna are about 10m long What’s a “Yagi” ?

  22. A Smaller Yagi Antenna The elements of this antenna are about 35 cm long

  23. One More Yagi Beam Three beam antennas on one boom. At EI4IS overlooking Cork harbour.

  24. Let’s Assemble an Antenna Now, we’re going to take a few moments to put together a small Yagi beam antenna which is designed to operate at 144 megaHertz. So, its elements are just about one metre long.

  25. Thank You!

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