Hi there!
I'm new and I tried to look around in existing threads... but I couldn't exactly find what I need. I've built a simple AM radio transmitter with cheap equipment. It's for a science project.
**broken link removed**
I amplify the signal that goes into my Ipod's headphones, and I add an Offset to it with a simple pair of TL072CN Op-amps (the amplification does not appear on this diagram). Then, with just an AD633JN multiplier and an astable multivibrator (another TL072CN, see diagram below), I do the Amplitude Modulation and have a signal of about 0.80 MHz.
For all this equiment to work, I have also built my own symetrical -15V/+15V alimentation using transformers, regulators, capacitors and diode bridges. So far, it's cost me very little money, I will not give the details of how I built this symetrical alimentation, since it's not what I'm worried about.
**broken link removed**
Now, I would like to broadcast this signal. I have 100 meters of cable that I intend to use as my antenna. I need to amplify it beforehand. The problem is: I can't really use an Op-amp to do the job. I'm guessing if I want to broadcast my signal over a 3 mile radius, I need better than an Op-amp...
... So: I'm considering the possibility of using a Push-pull amplifier using transistors, but I have a problem: this is beyond my knowledge! I know how to use Op-amps, multipliers and other simple kind of equipments, but I have no idea how transistors and Push-pull amplifiers work. I'm only considering this option since it's advice I've received from a store keeper, but I have no idea how qualified this store keeper really is.
My question is: Is it a good idea to use a Push-pull amplifier to amplify my 0.80 MHz signal in order to broadcast it over a long distance? What is the bandwidth of such a system? If a Push-pull is a bad idea, how should I amplify my signal before plugging it into the antenna?
Thanks a lot!
I'm new and I tried to look around in existing threads... but I couldn't exactly find what I need. I've built a simple AM radio transmitter with cheap equipment. It's for a science project.
**broken link removed**
I amplify the signal that goes into my Ipod's headphones, and I add an Offset to it with a simple pair of TL072CN Op-amps (the amplification does not appear on this diagram). Then, with just an AD633JN multiplier and an astable multivibrator (another TL072CN, see diagram below), I do the Amplitude Modulation and have a signal of about 0.80 MHz.
For all this equiment to work, I have also built my own symetrical -15V/+15V alimentation using transformers, regulators, capacitors and diode bridges. So far, it's cost me very little money, I will not give the details of how I built this symetrical alimentation, since it's not what I'm worried about.
**broken link removed**
Now, I would like to broadcast this signal. I have 100 meters of cable that I intend to use as my antenna. I need to amplify it beforehand. The problem is: I can't really use an Op-amp to do the job. I'm guessing if I want to broadcast my signal over a 3 mile radius, I need better than an Op-amp...
... So: I'm considering the possibility of using a Push-pull amplifier using transistors, but I have a problem: this is beyond my knowledge! I know how to use Op-amps, multipliers and other simple kind of equipments, but I have no idea how transistors and Push-pull amplifiers work. I'm only considering this option since it's advice I've received from a store keeper, but I have no idea how qualified this store keeper really is.
My question is: Is it a good idea to use a Push-pull amplifier to amplify my 0.80 MHz signal in order to broadcast it over a long distance? What is the bandwidth of such a system? If a Push-pull is a bad idea, how should I amplify my signal before plugging it into the antenna?
Thanks a lot!