I think you would be probably better off starting with something veru
simple, like a crystal radio (http://en.wikipedia.org/wiki/Crystal_radio).

The AM demodulator is a simple germanium diode -- in extreme case you do not
even use anything else, only the diode, a long antenna and a head phone.
Then everything else is just an add-on or plug-in if you like it that way.
So you can add as an add-on a resonant for tuning to a specific station,
then a simple audio amp, later on an RF amp so that finally you get a very
basic radio receiver.

Tamas



On Wed, Mar 31, 2010 at 7:27 AM, solarwind <x.solarwind.x@gmail.com> wrote:

> I've been very interested in electrical engineering and radio
> recently. I've been trying to learn how radio waves tie into
> electrical engineering. How do we create them? How do we receive them?
> I've read the howstuffworks article as well as some Wikipedia pages on
> the matter, but still do not know exactly how they "work".
>
> For example, a very simple 1 MHz AM transmitter is described here:
> http://sci-toys.com/scitoys/scitoys/radio/am_transmitter.html
>
> I am referring to the image here:
> http://sci-toys.com/scitoys/scitoys/radio/xmitter_schematic.gif
>
> I understand that the top left pin of the crystal oscillator is the
> input for some voltage. So assuming that I provide a steady +5 volts
> on that pin, what will I see on the output pin (top right)? Will I see
> a 1 MHz wave with a peak voltage of +5 volts? Or will it have an RMS
> voltage of 5 volts?
>
> How is the radio wave generated in this case? If I stick an
> appropriately sized antenna on the output pin, how is the radio wave
> generated? Why is it generated? Is it because of the oscillating
> potential difference across the output pin and ground?
>
> What governs the output power of the radio wave? How do we generate a
> more "powerful" signal? Assuming the photon theory of electromagnetic
> radiation (if that is the correct theory to use here), does the output
> power refer to the number of photons emitted/time? If so, how do we
> increase the power? And why are the photons emitted in the first
> place?
>
> On the receiving end, assuming a properly sized antenna, how is the
> radio wave "received"? When a radio wave strikes the antenna, what
> happens? If I were to have a long, straight piece of wire and clip two
> terminals of a sensitive oscilloscope to each end of that wire, will I
> be able to see the wave (assuming a powerful enough transmitter)? If
> not, why not?
>
> I know bits and pieces of things but I'm still not able to see the big
> picture here. I can only understand this stuff if I know the
> fundamentals on a very low level.
>
> I'm really trying to learn this stuff, and I have searched in several
> books and on the Internet, but it is proving to be a difficult task to
> find this information. I know you guys are the best people to ask. So
> here I am.
> --
> http://www.piclist.com PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>



-- 
int main() { char *a,*s,*q; printf(s="int main() { char *a,*s,*q;
printf(s=%s%s%s, q=%s%s%s%s,s,q,q,a=%s%s%s%s,q,q,q,a,a,q); }",
q="\"",s,q,q,a="\\",q,q,q,a,a,q); }
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View/change your membership options at
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