Q: it says that you have adapted the coil pick ups - what does this mean ?
A: basically, this technology has limiters applied in order to prevent them being used for certain surveillance practices. I buy them from the factory and remove the limiters that inhibit certain signals. This means that they are able to capture a wider and more fascinating range of signals.
Just found this linkI followed that link and now I also am puzzled as to what sort of limiter would prevent a coil pickup from being used for snooping purposes.
This page also mention induction receivers and recommend telephone pickup coil or 100mh air core.There was no further information about the nature of the limiting circuitry, or the means of boosting the signal level, but perhaps the coils I bought were not the type with limitations, I couldn’t tell.
The author of the blog above also searched for a "limiter" but found nothingAND, now I am wondering if the "limiter" that the supplier removes is simply a series resistor, or possily a two-resistor voltage divider. That would limit the amplitude of the signal and probably put it below the noise level of a typical cheap amplifier module.
Because of the absence of crystalline structure amorphous alloys are magnetically soft (lower coercivity, lower core loss, higher permeability). High resistivity gives lower loss at higher frequencies. The losses are among the lowest of any known magnetic materials
My guess is that the telephone coils already have a relatively softer core because it would cost less and be easier to shape into the desired form. So you may already be close to what you are looking for. You may be able to experiment by making a coupling loop out of a few turns of wire and then usin a signal generator to drive it, while noting the relative response as the frequency is varied.Even if it is not perfect it could give you a good insight into what your pickup can do.Telephone pickup coil are good for general listening, but for some devices (clocks) not sensitive and precise enough.
Not having the informations concerning the mentioned "limiter" and the "wider range of signals", the amorphous core seems to be an interesting (and cheaper) choice.
|Thread starter||Similar threads||Forum||Replies||Date|
|F||Coil-gun circuit-DC coil pickup harmful EMFs?||Wireless & RF Design||1|
|really long magnetic pickup||Sensor Design & Implementation||14|
|M||Splitting the output of a VRS magnetic pickup||Sensor Design & Implementation||8|
|R||3503 Hall effect sensor as an electromechanical pickup||Sensor Design & Implementation||2|
|R||Guitar pickup winder: wiring diagram help||General Electronics Chat||5|
by Jake Hertz
by Jake Hertz
by Ikimi .O
by Rushi Patel