Hi all, I am not sure if I am on right place.
I would like to know how to transmit and receive information over antenna WITHOUT any existing devices (like Xbee, rf link, etc), in other words, to make your own transmitter and receiver. As example you can take a cheap rc car controller and receiver. How do they work, and how efficient they are ? How hard is it to make by yourself ? Of course I am talking about making it with arduino, but if you have any docs that don't include arduino, you can share that too.
I am particularly interested in schematic and protocol.
Thanks, Amer.
Sorry nickatredbox, but this is not what I am looking for. I was looking for communication using hand-made antenna, not xBee, or any other module.
You need something to transmit your signal. i.e. you cannot connect a piece of wire ("..hand-made antenna...")to an arduino and expect it to transmit.
You need to get a very basic understanding of how radio works before looking for some basic tutorials.
Have a look at http://www.open.com.au/mikem/arduino/VirtualWire.pdf and http://www.open.com.au/mikem/arduino/VirtualWire-1.9.zip to get a understanding of modulation and encoding. This library, by Mike, who also contributes to these forums, runs on basic modules but you can still learn from the code despite your aversion to modules.
If you are keen on making your own, have a look at making some basic low frequency AM type radios, e.g. TE Index for website and then adapting the code above to encode your transmission. You may want to look up "manchester encoding" as well.
If you want to roll up your sleeves and get arm deep in the "nuts and bolts" or radio, from hardware to software, then get started with the above and come back.
If you merely need an application to transmit a signal between two arduinos, then there are some excellent radio modules for a fraction of the cost of Xbees (and mature libraries to drive them) which you could use.
Thank you for your answering, I haven't been here for a long time. I didn't know what actually to ask back then, turns out I was just looking for a way to make a modulator/demodulator, so I can transmit/recieve something.
Try Googling modulation, demodulation, also some studies about RF electronics would help.