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I got really excited by the "Build a computer controlled radio transmitter" instructable (http://www.instructables.com/id/Build-a-computer-controlled-radio-transmitter/ ) but wanted to use my telegraph key rather than have the computer send the code.
So here is a photo of my completed transmitter housed in WALL-E and with an old telegraph key I picked up at an antique market.
Also shown is a schematic. I used a 1 Mhz oscillator as recommended in the above instructable. I used a short section of a coat hanger for the antenna. I added an LED with resistor and a 9 volt battery.
I would refer you to the above above link for technical details as I have no knowledge of electronics and can barely operate a soldering iron.
This transmitter works very well and sends a strong signal to the AM radio. The signal I get is mostly "buzz buzz" and I have to play with the tuner a bit to get a signal I like. Mostly it produces a spark gap sound. Occasionally, if my printer is turned on (?), I get a pleasant "beep beep" sound. Using headphones helps. I added the LED so I could practice with the radio on or off. Range is about 2 meters.
I am now learning Morse Code and it's kind of fun. There is something more exciting about actually sending your code over the air rather than just using a buzzer attached to your key.
I want to give all credit for the technical aspects of this implementation to the above link. Nothing new here except another good utilization of WALL-E.
Update: I took a little sound board out of a jump rope that plays a little ditty and wired it in place of my telegraph key and it transmitted the ditty to the am radio perfectly. Now I am looking for a toy that just plays a single tone and I will use that as the sounder for my telegraph key and transmit that signal to practice my keying.
So here is a photo of my completed transmitter housed in WALL-E and with an old telegraph key I picked up at an antique market.
Also shown is a schematic. I used a 1 Mhz oscillator as recommended in the above instructable. I used a short section of a coat hanger for the antenna. I added an LED with resistor and a 9 volt battery.
I would refer you to the above above link for technical details as I have no knowledge of electronics and can barely operate a soldering iron.
This transmitter works very well and sends a strong signal to the AM radio. The signal I get is mostly "buzz buzz" and I have to play with the tuner a bit to get a signal I like. Mostly it produces a spark gap sound. Occasionally, if my printer is turned on (?), I get a pleasant "beep beep" sound. Using headphones helps. I added the LED so I could practice with the radio on or off. Range is about 2 meters.
I am now learning Morse Code and it's kind of fun. There is something more exciting about actually sending your code over the air rather than just using a buzzer attached to your key.
I want to give all credit for the technical aspects of this implementation to the above link. Nothing new here except another good utilization of WALL-E.
Update: I took a little sound board out of a jump rope that plays a little ditty and wired it in place of my telegraph key and it transmitted the ditty to the am radio perfectly. Now I am looking for a toy that just plays a single tone and I will use that as the sounder for my telegraph key and transmit that signal to practice my keying.
A larger antenna will definitely increase range but then you may run into legal issues if you are not a licensed ham operator. A higher hertz will just change the frequency of broadcast and reception. Not sure about the voltage but I think you would not want any higher than 9 volts. These are just assumptions based on the comments I read in the above link.