How do you tune the sensors?

[Craig Passeno]

I am building Phil Barnes' mag, with toroidal coils wound with 14 guage. the magnetometer seems to be working, it sounds just like I htink it should, except I cant get a ping, just the static and click of the switch. I havent tuned it, and I hope that is why. I dont know where to begin, do I just start throwing in any old capacitor and try it untill it sounds good? I have access to a oscilliscope if its needed... why wont it ping??
thanks
Craig

[Phil Barnes]

Re: How do you tune the sensors?

Hi Craig,

Here is how I tuned my sensors.

Set your audio generator to the precession frequency expected at your location. In my location here in Southern California the frequency is 2025 Hz. (This precession frequency is determined by the strength of the earths magnetic field at your loaction on the surface of the earth.)

Connect the audio generator to any multi-turn coil which can be located near or around one of the two sensors. The test coil will induce the signal generator frequency into the sensor.

Connect an oscilloscope or ACVM across the sensors terminals. Observe the sensor output signal and select tuning capacitors across the sensors for maximum output from the sensors.