Osciloskope

[BKY1337]

Ok, i can not get such a nice wave like you. I have played with the settings.

But its ok, thanks for your help. I will use the multimeter for the new coil and hope for 35 cm +.

[dbanner]

Also i forgot to mention that buffer circuit has attenuation resistor, thats why it looks small(amplitude)

[dbanner]

I dont think it gives accurate voltage using this scope, only displays waveform. Soundcard is AC coupled. Look at pic in post#26, this shows the freq, measured by software. Click on freq, tab on software to display spectrum analyzer window where freq. of wave is displayed. There are three jacks that are associated with soundcard, I used the microphone(pink), not green(headphone out) or blue(line in). I built a buffer circuit between soundcard and circuit under test. The titles all say Tx.

[BKY1337]

This is a nice Wave but i can see 3,5m which means 3,5 mV per square or not?

Is this TX or RX?

Have you used MIC or Line IN? I used MIC with 48.000 hz because of the software.

[green]

Here are my screenshots i just took of me TX oscillator.

Reply #22 suggests 14.5kHz. Your scope picture looks closer to 420Hz, maybe I'm reading it wrong?

[dbanner]

Press run/stop button to freeze waveform and save option appears on screen.

[dbanner]

What you are seeing for your waveform was a harmonic. You need to increase timebase, and also the yellow crosshairs on soundscope screen, double click on it and drag it up to waveform to get it to trigger so you can see still waveform.

[dbanner]

And here is oscillating main freq.

[dbanner]

Here are my screenshots i just took of me TX oscillator.

[BKY1337]

This was just a test with my old coil which is already made. But thanks for your help.
I will make a new coil when my graphite spray is here.

I dont think that the frequencies are correct. But i dont know how they should be.
I have thought 14,5 and the other one 13,95 at the same board connectors.
Maybe i have swapped the coils while building it.

I used this coil before but its clackering all the time. Only when i turn the pot all the way down its silent.

The inductances are nearly dead on. I have built the coil with measuring the frequencies with my DMM.
I checked them later and they were ok.

Im very interested in your screenshots. I will measure the frequencies and post them here.

EDIT: I got 13,68 kHz with the DMM at TX. I think something is wrong.

[dbanner]

It just so happens that i have tgsl on workbench, I'll run TX oscillator through soundcard scope program and take screeshots so you can see. Are you currently working on tgsl?

[dbanner]

Concentrate on getting your TX to oscillate at as close to 14.5KHZ first. Looks like your TX inductance is a bit too low. You need to add a few more turns of wire.

[dbanner]

TX inductance should be 6mH and RX should be 6.5mH or as close as you can get. What are your measured inductances of your TX and RX?

[dbanner]

Something is wrong, I assume your TX waveform is red. I think Tx frequency should be around 14.5Khz, I'll have to check. I have some screenshots of my waveforms I took with Zietnitz scope on my TGSL. I'll look for them. Meantime, did you read this?

[BKY1337]

I have an Inductance meter.
I made a screenshot of my soundcard oscilloscope.

I got 13,67 khz for RX and 13,71 for Tx. Tx measured directly and Rx at Pin 1 Op amp.