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Question by chocobabu: How does a ham radio work ?
i need to make a project on how a ham radio works.
i need the basic information on its working and ints components which is easy to understand and yet complete. please help ..
Best answer:
Answer by HardwareHacker
The answer to this depends on what kind of level of audience you are going to be presenting this to.
I have included links to block diagrams and descriptions of a basic AM transmitter and receiver (like a Ham operator would use).
Good luck!
What do you think? Answer below!
Ham radio is a means of communication between two amateur operators. At no time, can any amateur operator receive compensation for their communications, with the exceptions of school teachers using a demonstration as part of a regular unit in their classroom.
To communicate you need something to send with, a transmitter, and something to listen to, a receiver. For most operations in the 21st century, the transmitter and receiver are combined in a single unit, called a transceiver. The radio signals are sent from the transmitter, to be picked up by a receiver, and amplified for a device to interpret them.
Most communication is by either voice or morse code, though voice is probably a majority mode now. These kinds of communication are interpreted by loudspeakers or headsets, very much like the kind of radio you listen to in the car. The difference is that there must be a two way communication, since broadcasting is prohibited, except in special circumstances when bulletins may be transmitted by special arrangement. No music is to be transmitted in any circumstance.
Other forms of interpreters may be a computer, or a TV set. Yes, hams can send information from one computer to another, or through visual modes like slow scan (with a narrow bandwidth) or fast scan (with a wide bandwidth), and all through the radio.
A transmitter takes a voice, for instance, and takes that audio signal through a microphone, changing it to electrical impulses. These electrical impulses follow the same patterns as the voice, and then these are modulated to sort of piggy back them on a radio signal, generated by an oscillator, and amplified, and sent to an antenna.
A receiver picks up these radio signals, with the voice added, through an antenna, and demodulates them, back into an audible signal, then amplifies them so they can be heard, and sends them out through the
loudspeaker or headset.
There are many different signals on the air at any one time, so tuned circuits are used at the transmitter, to select an empty space to send a message, and at the receiver to pick the sent message out of all the others.
How do these signals get from the transmitter to the receiver? They travel through the atmosphere. Radio signals will travel in different directions. Some travel in a straight line (or arc, since gravity acts on electrons too, and they thus follow the curvature of the earth), others travel up, and the direction they take is important to how far they will go. These upward signals are what is responsible for what is called skip.
Skip is the process by which a radio wave travels up into the atmosphere and bounces off the ionosphere, and lands somewhere else on earth.
This metaphor is a bit weak, since it doesn’t take into consideration that the earth is curved, but it sort of explains why some signals go further than others.
If you take a rubber ball and you drop it on the floor, it is striking the floor at a 90 degree angle to a plane extending outward from your hand. This is a very high angle, and you’ll notice that the ball bounces almost straight up. If a signal is sent at a very high angle of radiation, it will come back almost straight down, and be received very near to the transmitter.
Let’s take the same ball and toss it away from us a little. Lets say for example, that it strikes the floor at an angle about 30 degrees relative to the floor. When it bounces, it doesn’t come back to us, it bounces further away. A radio signal does approximately the same thing, except that the earth it lands on is curved (or at least the area it encompasses is large enough to notice the curve, unlike the floor), and the ionosphere is also curved, so that will alter the angle of its return slightly. If you tried the same trick with the ball on a skateboard track, where there is a gently curved area, it might act somewhat more like it will in space.
Frequency of the signal is also a factor. A signal at the Long wave frequencies will be more inclined to travel in a straight line (or arc for us Earthlings), a signal in the short wave frequencies (3-30 MHz)will do both, line of sight, and skip, while signals at very high frequencies and higher (30 MHz up to the visible light spectrum) will be more likely to travel in the line of sight. There is some mixture in here, but the predominant uses at these frequencies involve those patterns.
If you are interested in more details, I invite you to take a look at this link.
The American Radio Relay League is our national organization, and it will celebrate its 95th year this year. That’s a little weird, thinking that I was first a member of the ARRL when I was first licensed, in 1968, and the ARRL will turn 95 and I will turn 55 this year.
I hope that helped, it’s about as basic as I can get on the basics of radio.
The link will also take you to something called We do that radio.org, which is a very nicely done page on what hams to with the techn
For a basic overview look at this file:
http://www.arrl.org/FandES/tbp/radio-lab/RLH%20UNIT%204.pdf
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