Carbon60 wrote: ↑Sun Mar 20, 2022 7:25 am
rsfoto wrote: ↑Sat Mar 19, 2022 8:30 pm
What do you see in the screen at the micro volt level ?
Hi Stuart,
Below a graph of about 40 minutes of time taken with onyl one coil. Just wound the second in opposite direction and graphing for an hour at the moment. That is the maximum time my multimeter allows to graph.
If you check that the variation is between 1.2 µV to about 1.8 µV or 0.0000012 to 0.0000018 V ¿ correct ?
It shows how electrically noisy it is in your workshop, which is to be expected. If you set up your sensor in the location where you you intend to install your magnetometer you’ll be able to determine how noisy it is there. If it is much quieter on your scope, which would have to be set some metres away, then you might be in with a chance. The challenge with your system is that the connecting wire between the sensor and your detector will also act as a ‘sensor’ and will suffer from interference if not properly shielded.
FGM sensors work by generating an output frequency rather than fluctuating voltage. It’s this variable frequency that I measure. Voltage outputs are subject to extraneous effects created between the sensor and the detector, messing up your geomagnetic data. You could try to configure yours to drive a voltage controlled frequency generator close to the sensor, but then this itself will create its own magnetic field which will affect the sensor….. tricky.
Stu.
Hi Stuart,
It’s this variable frequency that I measure.
OH, so this a FM matter and not AM matter . Need to read more about this ... All what I have read so far talks about voltage differences ...
Thanks. we are talking here about microV not even milliV according to what I see on the screen. The lower value even has nanoV ...
OK, right now I am graphing the AC voltage generated by the sensor coil to see what comes out there.
Playing around a bit and putting some ferrous metals near the the whole wannabe
FGM does change the AC voltage of the output. Even putting my hand over the FGM changes the output voltage ... Interesting
Look at the images below running the Franken FGM over hours and putting a screwdriver on top of the coils
No on purpose Disturbance running lonely in the corner. mVAC difference is only 0.3543 mV AC
Yes on purpose Disturbance by putting a screwdriver on top of the coils. Difference is 2.6332 mV AC
If you look closely on the end of the disturbed graph you can see a drop and that was me approaching with the camera to image the mutlimeter screen ...
Now just find out what Gauss values are this
will need to investigate how to measure that in a simple way. Are there simple ways for this ?
one things leads to the next one