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How to make a Super Sesitive AM transiver from scratch

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Shukufuku

New Member
I'm working on a project that requires a extreemly sensitive AM transiever. It must be able to pick up/broadcast a signal equivilant to a 3 watt radio transmitter.
I need to know what all parts are neede and how to put it all together, I can read scematics. I would just use any old scematic for radios, but I don't know anything about tank circuts. So any ifo on tank circuts or just a scematic on how to make my specific radio would be greatly appreciated.
Thanks in advanced!
 

Shukufuku

New Member
Thanks for the link.
It may sound stupied but, I just have one question about what they say. In the last paragraph in the Resonance section, when they say "the higher the inductance and the lower the capacitance, the narrower the filter bandwidth." Do they mean the more precise the tuning is, or what?
 

BrownOut

Banned
Thanks for the link.
It may sound stupied but, I just have one question about what they say. In the last paragraph in the Resonance section, when they say "the higher the inductance and the lower the capacitance, the narrower the filter bandwidth." Do they mean the more precise the tuning is, or what?

That was only for a series resonate circuit. For a parallel resonate one, the coefficient is the opposite. The reason for this is they are assuming circuit resistance, but they don't show it in the diagram or even in the equations. They just throw it out without giving any idea where it came from. It's not stupid to get confused. You need to read a much, much better reference, and even then, you probably need 2 years of engineering to understan it.

That said, designing and building a sensitive receiver is hard. Best to acquire a schematic, or even better, a kit, of a well designed unit.
 

Shukufuku

New Member
Thank-you for the info, I unfortunately cannot use schematics though. This is because the radio receiver must be tuned to the range of 30-60 KHz, witch I doubt any circuit out there will show you how to tune a AM radio to that range. So I need to understand how to tune the radio to that range and then I can use a Schematic. I just need enough knowledge on the matter to make the tank circuit tuned to that range. If anyone is willing to teach I am willing to learn. Thank-you everyone for the help.
 

Shukufuku

New Member
I am still researching tank circuts on my own as well as hoping for help from here. (just didn't want you all to think I was wanting the answere to fall in my lap)
 

BrownOut

Banned
What is the purpose of this project? Is it an assignmemt? Are you trying to communicate from an isolated place? Do you have any training in electronics? Why do you need to research tank circuits? Have you taken any advanced mathemetacs? Do you know how to do LaPlace analysis? Have you ever built a tank circiut before? Is there a public library where you live? Don't expect to learn everything you need to build a transciever on the internet.

Knowing a little more about your goals/education/experience might help us to help you.
 
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Shukufuku

New Member
I have taken a basic Electronics course in High school. So I know what the components are and how to read a schematic and a few, very basic, equations. My project is entirely personal, it is to pick up radio waves from the Human Brain. Its basicly in reverse of the Neurophone. No I have not taken any advanced Math. I have never heard of LaPlace analysis. Yes I have built a radio, but I never understood how to tune the tank circut. Yes, there is a public library, I have read all of their books on the matter, I'm still in the dark. I will keep it in mind to look in more places more, thank-you.
 

Shukufuku

New Member
I've been trying to get my dad to help me out, he worked on radios in the military for about 20 years. He says he doesn't remember much. I keep trying to tell him not much is better than nothing.
 

BrownOut

Banned
Shukifuku - I'm sorry if I sound condescending. You're taking on a pretty big project. Even experienced engineers find RF a challenge. Can you get a copy of the ARRL Handbook at your library? They have a chapter on AC circuits that goes over some of this stuff. I'd be happy to try to answer any questions you have. But it's hard to post a turtorial on a forum such as this. I've thought of posting one on my website, but it won't do you much good as you need answers now. Feel free to ask any more questions, and I'l try to think of a way to put up some information.
 
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Shukufuku

New Member
It must be in the 30-60 KHz range because according to Patrick Flanagan's research, the brain's carrier frequency is always in that range. I know the Neurophone works, but that doesn't guarantee that this will work, but I'm very curious if it will. If not, I still need the info for a few other projects
 

Shukufuku

New Member
Thank-you very much! I understand that this is a difficult project, but I must do what I can, not matter how long it takes. I also understand that teaching such things is near impossible, at best, on a forum. But I'll take what I can get :)
I will check on the book immediately. thanks again!
 

BrownOut

Banned
As for your earlier questions; to reiterate, circuit selectivity depends on the existance of resistance, which is usually not shown on the schematic because the resistance is parasitic ( which means it's an unintended part of the components used to build the circuit ) Generally, the resistance in a tank circuit comes mostly from the coils, thought the capacitors donate part of it too. Controlling the effects of this resistance determines the selectivity of the circuit. These effects are affected by the circuit topology and the values of the circuit components.
 
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blueroomelectronics

Well-Known Member
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Shukufuku

New Member
That has nothing to do with what I'm trying to make! My device is simply to read ones thoughts, not to diagnose or cure any illnesses. Besides that, this uses Amplitude Modulated radio waves not pulsed magnetic waves. As I said, Its based off of Patrick Flanagan's Neurophone witch broadcasts sound almost directly into the brain. So even if your nerve deaf you can still hear with the device. I am simply trying to go the other way around, take the sound out of the brain instead of put it in. The Neurophone has been scientifically documented to work. The device you have linked to is NOT even SIMILAR, let alone helpful. But thank-you for trying to assist.
 

Shukufuku

New Member
Mybe it does and maybe it doesn't. How do you know? I know it does, but the question is, is it that simple to decode them? (everything that uses electricty send radio waves, weak but still present)
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
Mybe it does and maybe it doesn't. How do you know? I know it does, but the question is, is it that simple to decode them? (everything that uses electricty send radio waves, weak but still present)

If you know so much about it, why aren't you doing it :p

You entire premise is wrong to start with, everything that uses electricity DOES NOT send radio waves.

In the case of the brain, the levels of elecricity are so incredibly tiny that you need direct contact to the head with electrodes, and VERY, VERY high gain amplifiers to detect them.
 
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