another way to send cw on mumble using the IPHONE and a special INDUCTION COIL to iphone MIC interface

[Chuck Vaughn]

live demo of the setup here:

https://youtu.be/pS2KBdCAFDg

here is a picture of the induction coils underneath the iphone

the MIC of the iphone is above the LEFT COIL

using VLF at 19Khz and AM modulated CW....

the iphone can pick this up for the mumble input...

and also receive the same with the RIGHT COIL underneath the iphone speaker...

almost none of us can hear with our ear drums, CW at 19Khz VLF freq....

so the iphone speaker will be silent to 19Khz CW  by sound over air transmission to the ear drums etc...

but the ferrite bobbin inductor COIL does pick up the 19Khz CW AM signal and it goes to a simple

VLF AM RECEIVER that demod's the 19Khz CW back into the typical (+-)700 hertz CW audio tones