I am interested in getting into learning radio. I am looking to make a radio transmitter (and possibly a receiver) at any frequency. I would like to make the antenna and what ever else I need. I wish to generate a single square wave with it. I am looking for output power to be from 1 watt to 50 watts.
any information you provide on this would be much appreciated.
Umm, try a ham radio forum?
I am looking for output power to be from 1 watt to 50 watts.
"Learning radio" would involve learning about the laws governing who can use what frequencies at what power levels. 1 to 50 watts is not in the "learning radio" power band.
CrossRoads:
Umm, try a ham radio forum?
50W, square wave, at any frequency...It sounds like he wants to build a jammer.
Jammer Shield...
it's
Sparkgapuino
LOL, Sparkgapuino! Good one 
I really just wanted to understand how to make a transmitter of any kind and thought a square wave would be the simplest. I still do not even understand how to generate a radio wave with an Arduino. I believe the Arduino can broadcast on am radio frequencies? How can I go about doing this.
Preferrred method would be to input data into a real transmitter so that real receiver can pick it up.
And use VirtualWire library
LOL. That deserves a karma point.
The Arduino transmits radio signals already. Get an AM radio and put it next to an Arduino to hear the sound of Square Waves from a distance of 25.4 mm. Write a sketch to change the sounds transmitted by the Arduino. Tell us about the sounds you make with Arduino AM radio WLAN wireless local area network experiments. Record the audio and let me hear it.
Add an antenna to Arduino to increase the range of its interference on the AM radio medium wave band.
arduinoPi:
I really just wanted to understand how to make a transmitter of any kind and thought a square wave would be the simplest. I still do not even understand how to generate a radio wave with an Arduino. I believe the Arduino can broadcast on am radio frequencies? How can I go about doing this.
A sine wave is simplest, it is a single frequency. A square wave is multiple frequencies. An Arduino isn't particularly meant to generate a radio signal, but it does, like all computers and digital devices, generate some amount of radio frequency interference (RFI). Put a running Arduino next to an AM radio to hear it. (Edit: AmbiLobe beat me to it.)
Is that the one with the Wimshurst chip or the one with the bigger Van Der Graaf chip?
This might be relevant:
Building Radio Transmitters that actually work, ie have efficiences of 50% or more is not a trivial
exercise, and requires a good understanding of impedance matching networks , and an understanding of antenna design.
The ARRL handbook is not a bad start, but the learning curve is steep.
http://www.arrl.org/shop/ARRL-Handbook-2013-Hardcover-Edition
If you are looking at building Transmitters in the UHF or SHF bands , 400 Mhz up to 2.4 Ghz
I would say forget it initially, as its not usually practical for a home hobbyist.
This is the best example I have seen. How can I amplify the signal to make the range longer?
Pi,
the link to ARRL was a good start for you.
If you are serious about having enough power to be heard any further than next door then you really need to take a look at getting licensed. In the U.S. it's inexpensive and there is plenty of study material available to pass the test.
Be warned, "Before you can get on the air, you need to be licensed and know the rules to operate legally."
See here for taking the first steps to get your license and not causing unlawful interference which probably won't get you solitary confinement, but will certainly get you fined.
I think I will get registered but I have one question. In Nick Gammon example where is the power to transmit being used? How would I calculate the power used?
What happens when I use a wire longer than 5 inches? Will it use more power?
arduinoPi:
This is the best example I have seen. How can I amplify the signal to make the range longer?
I don't know. I'm not that much of a RF expert. First, I probably shouldn't since it is a standard radio frequency. Second, I have no idea how to do it. Probably a good thing.
"How can I amplify the signal to make the range longer?"
Please do not make the range longer by using RF transistors connected to a wire fence by the cow pasture. If you disobey my request, you might interfere with my reception of radio signals provided by advanced radio equipment.
How does changing the pin from input to output generate a radio wave? why doesn't making the pin go from low to high generate a a radio wave?