Sorry, but I think you're just imagining things - you can't detect radio waves from the brain, it doesn't transmit them.

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)

Originally Posted by Shukufuku

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

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.

Originally Posted by Shukufuku

Besides that, the entire purpose of this post is to get help on how to build the thing, not weather or not it works. But thanks for your opinion!

How can we give advice on building something that can't possibly work?, but for the frequencies you're talking about check out designs for atomic clock receivers.

I remember pyramid power.

Why do folks fall for such nonsense?

Originally Posted by Shukufuku

Are you building an electronic project or want to? Maybe you need some assistance? Come and submit your electronic questions here and let our experienced members find a solution." not we will determine if it works, even after you have show you obviously don't care if they think it does/doesn't.

You are missing the point that people who are very experienced are trying to save you the time and frustration of trying to build a circuit that will not work.
Instead of heading their advice, you reject their advice and state that you know better.
If you ask a question, why reject the expert advice you have received?

Originally Posted by Shukufuku

I just want to know how to make a reciver that is tuned for the range of 30-60 Khz.

You need to give a better definition of your requirements.
Do you want a receiver which can be tuned between 30 and 60 khz but only demodulates a narrow range of frequencies, typically 5khz.
Or, do you want a reciever which is receiving the whole band from 30 to 60 khz and demodulating the whole lot at once?

Tuned circuits for these frequencies require coils with many turns and can be a pain to wind.

Just recently I built a VLF receiving converter which takes signals in the range 0 to 500khz and converts then to 10.000Mhz to 10.500Mhz so that they can be heard on an existing HF communications receiver.
The converter was simply a 5pole 500khz low pass filter, which fed an SBL-1 double balance mixer. The local oscillator was a single transistor oscillator using a 10.000Mhz crystal for the frequency determining element.
The output of the mixer was fed straight into the antenna socket of the receiver (an Elecraft K2 which is actually and SSB transceiver, but just using the receiver here).

Depending on how you go about picking up the brain signals, you may have problems with off-air signals. You do not state where you are located, but there are some rather high power transmitters on these frequencies which are used by the navy etc for communication with submarines. You may have a few problems keeping those signals out of your receiver.

JimB

You might consider using one half of a CMAX time code receiver IC. For example, this one:

Digi-Key - 561-1007-5-ND (Manufacturer - CME8000-TLSH)

(download the data sheet for details).

This type of IC has the gain and demodulator that you need, however they assume that you want to receive only one or perhaps three specific frequencies, and so crystal filters are used. If you replace the crystal filter with a tunable filter, you might be able to use this IC for a broad range of frequencies. Beware that the IC gets good sensitivity by recieving a very narrow bandwidth by using a crystal filter. If you don't use a crystal filter, your sensitivity won't be as good as the data sheet says.

One important thing about your project is to realize that the antenna or transducer that you use will be critical to getting good sensitivity. Normally for picking up radio signals at these frequencies, the sensitivity of the reciever isn't all that important because the electrical noise in the environment is so high that your sensitivity is determined by that noise, not by your radio design. If you plan on using electrodes or something like that, make sure that they do not pick up radio signals or radio noise from the environment or you will also suffer a high "noise floor" and poor sensitivity. You could avoid this problem by performing all testing of human subjects inside a faraday cage.