TM 808 White's

[berreizeta]

The #215 calculator is theoretical and is used to know approximately how much capacitor you will need.





I adjust the coils with the oscillator and a function generator looking for the maximum signal,

then I do the fine adjustment with the Visual Analyzer program and function generator :





I will be with a margin of approximately 10 Hz, I don't know how to tune the coil closer....

[pito]

Use the coil arrangement as in post #197, add a 10nF or 100nF capacitor in parallel to the coil, do it first for Tx then for Rx, adjust for the max voltage in Rx, if adding a capacitor is causing voltage decreasing coils are in rezonanse or capacitor is to big.

10Hz,
if changing frequency by 10Hz is effecting amplitude in Rx that is not good, it will cause instability of the device, 100Hz or more is ok.

[ivconic]

https://www.geotech1.com/forums/forum/technology/coils/16950-tf-900_tm800/page10

[berreizeta]

Checking coil tuning at 6,533 Hz

RX :

https://www.youtube.com/watch?v=SIcBVaiZtHw

TX :

https://www.youtube.com/watch?v=en1JN9i5iqQ

[pito]

If your videos are respond to my post # 227 it is not what I meant, I was talking about mentioned by you to small margen 10 hz.

Checking coil tuning at 6,533 Hz = you don't need exact this number, just put 1 yellow capacitor with standard capacity close to 600 nF which is 680 nF in Tx then tune receiver to Tx frequency.
Tx frequency can be different what you have now but this is not important.

[berreizeta]

Ordered tm808 board to JLCPCB :

[pito]

Beautiful, and which program you are using ?
I am using ExpressPCB but there is no Gerber option.

Here is the small PCB,I need it in Gerber.
.

[berreizeta]

The best prog .: Sprint-Layout 6.0

Indicate me an email and I will send it to you

[pito]

I sent you a private message with your email address

[pito]

Just Tx and Rx tuned coil connected to oscilloscope, reaction noted at 80cm, with amplifier should be over 1m. I not happy with power of Tx, should be 2x more, probably transistor not good as in original.

[pito]

The best prog .: Sprint-Layout 6.0

Indicate me an email and I will send it to you

Thanks
I am trying figure out how to put all together.

[ivconic]

Just Tx and Rx tuned coil connected to oscilloscope, reaction noted at 80cm, with amplifier should be over 1m. I not happy with power of Tx, should be 2x more, probably transistor not good as in original...

I think coils are too close on your video...
Set them at 65-70cm apart and check again...

[pito]

With amplifier I have 110 cm.
Distance between coils don't affect the sensitivity much, here are the coils even closer.
The smaller the distance, the more difficult it is to balance.

[pito]

Now I have 130cm, with some inferences ( image is shaking )

https://www.youtube.com/shorts/nC5ajrUm47Q

[berreizeta]

How do you do that ?



At 1, I have 15V and 36mA to the coil.



In 2, I have 0.3V with the coils in null:



Low sensivity :

https://youtu.be/Z1aTZIuyVIo