Hello,
I have been working on building a crude transmitter/receiver who's signal can be measured through soil and rock. Like these "flushable transmitters"
https://www.prototek.net/Flushables.php.
There is a great article about low frequency magnetic communication that I have been referring to:
http://ww1.microchip.com/downloads/en/AppNotes/00232B.pdf
The first trial circuit I have built is similar to that built in the microchip document, except for different capacitance and inductor (I was trying to roughly match industry standard 512 hz resonance). PIC PWM controls the recommended MOSFET (TC4421), which feeds the series tank circuit. I'm confident this is working as it should, because my oscilloscope measures almost identical to what LTSpice shows for voltage across the inductor(attached .pdf).
I can get a signal using a parallel tank circuit with identical components up to about 12 inches away, but I would like to stretch that to 10 or 15 feet if possible. The 600Ω resistance of the inductor is certainly limiting the voltage of the resonance peaks. Will it help my cause if I can get those resonant peaks to more like 200 volts like the microchip document shows? Also, so long as I maintain resonant frequency, will a larger antenna help on the receiving side? Something like a loop or ferrite rod antenna?
I'm a mechanical engineer who enjoys tinkering, so please bear with me! Thanks in advance!
I have been working on building a crude transmitter/receiver who's signal can be measured through soil and rock. Like these "flushable transmitters"
https://www.prototek.net/Flushables.php.
There is a great article about low frequency magnetic communication that I have been referring to:
http://ww1.microchip.com/downloads/en/AppNotes/00232B.pdf
The first trial circuit I have built is similar to that built in the microchip document, except for different capacitance and inductor (I was trying to roughly match industry standard 512 hz resonance). PIC PWM controls the recommended MOSFET (TC4421), which feeds the series tank circuit. I'm confident this is working as it should, because my oscilloscope measures almost identical to what LTSpice shows for voltage across the inductor(attached .pdf).
I can get a signal using a parallel tank circuit with identical components up to about 12 inches away, but I would like to stretch that to 10 or 15 feet if possible. The 600Ω resistance of the inductor is certainly limiting the voltage of the resonance peaks. Will it help my cause if I can get those resonant peaks to more like 200 volts like the microchip document shows? Also, so long as I maintain resonant frequency, will a larger antenna help on the receiving side? Something like a loop or ferrite rod antenna?
I'm a mechanical engineer who enjoys tinkering, so please bear with me! Thanks in advance!
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