If an aerial turns EM waves into current...

Can you put current into an aerial and have your own radio generator?

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lewiso1 (author) 10 years ago
LasVegas10 years ago
No. Feeding current into an aerial does not a transmitter make.
Feeding alternating current into an aerial does make a transmitter though. (Although you will probably actually have an alternating voltage source, which will induce a small current.) The frequency of the voltage determines the radio frequency. The length of the antenna is important though.
Get real. The message was an answer to the original question. Your semantics argument only confuses the topic.
I have to agree with billybobfett here. This has nothing to do with semantics, the answer is yes. It's the principle behind radio transmissions. All your AM-FM radios use this idea, making EM waves by feeding AC current through your aerial. In a nutshell, what is happening, is that charges are oscillating inside the aerial, inducing oscillating electric and magnetic fields, hence and EM wave. check out the electromagnetic induction and EM wave chapters of a physics textbook, or look up Hertz and his dipole antenna.
If you take the time to read the two lines making up the question, the answer is no. Sending current through an arial is not sufficient to generate radio. If you really want semantics; You need nothing but a magnet and a wire to generate radio. Want something discernible? Use a spark!
Ok. I'm having trouble working out whether you're being pedantic, by saying that the "current" refers to DC current, and not AC, in which case I should tell you to stop being pedantic. Or whether you're denying that sending AC current through an antenna will produce a radio signal entirely. In which case, I'd like to quietly point out that a quick search will show that the bulk of the evidence is weighted agaisnt you. Or you might be saying something completely different, and I have no idea what your point is. Also, its generally considered proper to back up and support what you are saying with facts. "No" does not mean anything unless it is supported with verifiable evidence.
Pedantic? Hardly. Go ahead and plug a 120V/60 Hertz into a car's arial... Did you generate Radio? If it were that easy, Marconi would have been a side note.

Hmmm.... And where was "No" used without back up and support of facts such as "Feeding current into an aerial does not a transmitter make." There was no mention of AC or DC, there was no mention of AM or FM. There was no mention of the length of the arial, nor how the current would bee feed through it. Just the term "current" and "arial" and with the given information the answer is a resounding "NO!"

Take a look at the Instructable here: Build a computer controlled radio transmitter

This example is about as basic as one could possibly get and have a viable transmitter. Did he just feed current through an arial? No! He introduced a frequency to the current and supplied Amplitude Modulation (AM).
Ok. I'm going to direct you to read the question.

The word "can", when used in its interrogative form, usually inquires as to whether an event has the possibility of occuring.
ie. Can a coin land on heads? This asks whether it is possible for a coin to land on heads.
Can the ball roll down the hill? This asks whether it is possible for the ball to roll down the hill.

The question that has been asked is:
Can you put current into an aerial and have your own radio generator? This asks whether it is possible to put current into an aerial, and generate radio waves.
If you put an AC current through the aerial at its resonant frequency, then you will generate a lot of radio. Thus, it IS POSSIBLE, to generate radio by feeding a current through the aerial. The answer to the above question is a resounding "YES!"

The question did not ask for the transmission of signal, only whether radio waves could be generated. Hence AM or FM has nothing to do with this. A simple AC signal will produce radio waves.

How the current is fed through is irrelevant, we are not considering that aspect of radio generation. We are given a current in the question. The method used to feed it through has no impact on the outcome.

And now to this instructable that you've put here. You've said, "Did he just feed current through an arial? No! He introduced a frequency to the current and supplied Amplitude Modulation"
Now this is all very well and good, but what the question is asking is whether current was fed through the arial. Yes, current was fed through the arial, though it was at a certain frequency. This, however, does not negate the fact that current was supplied.

In fact, I would dare say that just the terms "current", and "aerial", and the given information is sufficient. The first line says, "If an aerial turns EM waves into current". We know that the current that is being produced is an AC current. The "current" that is being referred to is the same current as the output of the aerial.
The question is ultimately asking about the functionality of the aerial when its role is reversed, similar to asking, can a motor function as a generator? If you were to say no to that, simply because I have not specified what type of motor, generator, name, brand and serial number, then I guess it's completely within your rights to say no to this too...
Well said.