Check this out, its called a "gravity wave detector" and is actually what I wanted to build.
Oh, fringe "science"...
Always amusing to see the results of old age leading into pseudo science and the paranormal or its cousins - but too bad, that many of those that venture off those limbs, present it with their "experience" (read: age) as a motor for sounding authoritative - Sadly, it happened to Tony vanRoon (gone but never forgotten! - No Tony, my abnormal sleeping patterns is not from reading John Connolly
) as well in his later years, where he started chasing free energy ideas, although he sure knew better in his working years - I hope it's not a given process, to start believing the paranormal as the brain deteriorates, but if it happens to me, I hope I'll amuse as much as I've been amused over the years
Do you think I can use any op amp chip for IC2? and what do I use for IC1?
Yes, you can use whatever op-amp you like.
HF-circuits. The capacitor at the input, together with parasitic elements makes up the "receiver antenna", which is band limited, but fairly wide. Then there's some crude 3dB LP filtering at the outputs. The first circuit seems to be a pain, with 2 potentiometers and 1 variable resistor *sigh*
They're in essence what I call Radio Moscow receivers... With Radio Moscow filtered out.
I sure wouldn't associate my name with any those circuits
I found a text mentioning that the range up to 300Hz is what they're after, probably because they weren't able to dig signals out of the white noise specter at higher frequencies (noisy circuits, lack of technique or whatever)
I also found another of these gizmos, one that makes a bit more sense when used for research...(Click pic for high resolution)
The cap (Cx) over the Rf
is a smarter way of achieving LP filtering, as it's then cut out of the amplification, leaving more headroom for the frequencies of interest and the simple AC-or-DC output gets it into a slightly more serious domain, however simple it is.
If you need more amplification (those Martians speak very softly
), just add an op-amp coupled as a low frequency audio amp.
A few things worth noting:
All such circuits will be very noisy, as the feedback resistor is large (to get a high gain) and large resistors produce more thermal noise.
The gain of the op-amp varies with the frequency of the input.
Max gain available from an op-amp is GBW
(you find the GBW
in the datasheet for the op-amp you use).
Your results will vary a lot with your building method (a solderless proto-board may give different results from day to day, depending on orientation, how near you are to the circuit, humidity of the air, temperature etc.).
Unless you're really sure about finding intelligent extra-terrestrial life, I wouldn't bother, but OTOH you may gain some valuable insight into op-amps by building one.