Build a computer controlled radio transmitter

Step 8 Congrats

Your all done.

A few tips:
-Get a good antenna. I heard about someone who did this with a 24.3MHz oscillator and a 10 meter antenna and sent his signal from California to Texas. I haven't tried testing mine outside my house yet, but it works pretty well here.

-Get a higher frequency oscillator if possible. If you have a SW radio then you can to this, otherwise stick with AM. If you use AM though be warned that your messages won't be private. Anyone can pick up an AM signal.

-Check your frequency. If your frequency is in an amatuer radio range then you will need a licence to run it. If it is in an AM range, you can only send your signal a few blocks (I think it's a mile) without a licence.

Hope you can use this to send secret messages to far away friends.

Comments

[bluescope93]

Gday,

Just a Question how do u send the Data to the Frequency Oscillator if all you are supplying to it is Power? , do you have a CW Key to turn the +9 Volts on and Off therefore creating a Morse Code Format?? , Or do u send the Audio for a Mono 3.5 or 6.5 Plug into a Radio or Computer and play a Tone or music??

Cheers and 73's
VK3FTIM
Tim

[Jasinqc]

Turning on and off the oscillator via the computer's DB (De) 9 port IS keying the oscillator. It can be unmodulated - - CW mode -- or modulated. In this case the computer program handles the selection and transmission of those modes.

Turning on the Carrier Wave - and then off - to form Morse code characters, is the very definition of CW mode.

Joe, N2QOJ

[Win7Maniac]

Great project. Is there a program like this one that will send music out the serial port like a radio broadcast? Could you use a 1.0000mHz oscillator and tune a normal radio into 1000kHz and listen to the music? Thanks Ryan

[kroq-gar78]

1. how would you receive a 24.3MHz signal with a radio? my pocket radio only goes up to ~1300KHz
2. my pocket radio is (# of MHz) * 100 , not (# of MHz) * 1000. I think that's how a lot of pocket radios are to save space