mstechca said:
Talking electronics declares this a typical FM transmitter.
For my receiver, I made the oscillator circuit in such a way that the tank circuit is connected to ground instead of VCC. Why? because I wanted to achieve higher gain. and I'm sure a common emitter amplifier is better than a common collector one. and I can tell that it is a common base amplifier for AC.
You might be 'sure', but you're completely wrong! - specific modes are better for specific purposes, there's no 'best' mode. For an oscillator the gain is almost completely irrelevant, it needs to provide just enough gain to provide oscillation - and NO MORE - any more will cause distortion, and provide nothing helpful at all.
But here is the question. If a receiver can almost be built the same way as a transmitter, and a receiver can cause interference (a.k.a. transmit signals), then why isn't there just an extremely simple method for me to take the transmitter above and convert it to a receiver without adding extra components (with the exception of the audio amplifier)?
You've been messing about with these for ages now, basically just changing things at random and seeing what happens. This isn't any way to build things!.
Why not build a proper radio?, instead of playing with crap super regen designs?.
I doubt you'll listen, or understand?, but I'll explain very simply about the evolution of these sorts of radios:
1) Crystal set - tuned circuit, detector, earpiece.
2) Amplified crystal set - tuned circuit, RF amplifier, detector, earpiece.
3) Regen receiver - same as 2), but you apply adjustable positive feedback around the RF amplifier, by adjusting the feedback to the point JUST BEFORE oscillation, you get the maximum possible gain from the single stage. You have to adjust the feedback control along with the tuning control all the time, in order to keep it just on the edge.
4) Super regen - basically the same as 3), except the continual complicated feedback adjustment has been removed - by making the RF stage oscillate as a lower frequency, you can make the RF stage burst in and out of RF oscillation, keeping it at the most sensitive point. An incoming signal will tend to stop the oscillation, and produce 'reasonably' clear audio. Big down side, it produces loads of RF interference, so isn't a good choice in these days!
Basically the regen and super regen were designed when active devices (either valves or transistors) were VERY expensive (think Pentium 4 processors!), so it was important to use as few as possible - who wants to build a PC and pay for four or five Pentium 4 processors?, when you could get 'almost' a similar performance from just one.