Simon @ Scitoys shows you how to build a computer controlled wireless transmitter – “How would you like to send text messages to your friends without wires, and without an Internet connection, and without paying monthly fees? In this project we will build a very simple radio transmitter that you attach to a serial port on your computer. The computer then runs a free program that converts words you type into radio signals that are decoded by another computer, using a cheap radio receiver, and a sound card. “ – Link.
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6 thoughts on “HOW TO – Build a computer controlled radio transmitter”
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Nice way to generate interference!
Switching an oscillator on and off means (i) frequency will not be stable as it won’t have time to settle)
(ii) you will cause wideband interference, known as impulse noise.
Most package type oscillators such as you use, will have a tri-state pin (read: enable). Switching this on and off will produce a much cleaner signal than doing the same to the power as the oscillator is always running, it is only the output that is being switched.
Not to mention, it’s probably illegal in many countries ,e.g. UK (use of an antenna to “transmit” the signal means you are actually transmitting – for which you need a licence.
Other than that, it’s a great idea! and if you like the idea of using radio to communicate, why not visit
http://www.arrl.org
or
http://www.rsgb.org.uk
Nice way to generate interference!
Switching an oscillator on and off means
(i) frequency will not be stable as it won’t have time to settle
(ii) you will cause wideband interference, known as impulse noise.
Most package type oscillators such as you use, will have a tri-state pin (read: enable). Switching this on and off will produce a much cleaner signal than doing the same to the power as the oscillator is always running, it is only the output that is being switched.
Not to mention, it’s probably illegal in many countries, e.g. UK (as the use of an antenna to “transmit” the signal means you are actually transmitting – for which you need a licence).
Other than that, it’s a great idea! and if you like the idea of using radio to communicate, why not visit
http://www.arrl.org
or
http://www.rsgb.org.uk
MAZY Gaint