Shield

[MaverickITA]

I know that only RX coil need shield.
I am wrong?

Are there many differences in shielding also TX or it is exactly the same?
In which case is mandatory shield also TX?

At the moment many use graphite spray but the problem is the housing.
I am using one model that do not have something to close it under.
Therefore I prefer to shield coils directly with adesive aluminium tape connected to ground.

I wait your help...
Thanks.

[Davor]

Some of my simulations show that shielding both Rx and Tx leads to less phase shift than shielding Rx alone. I prefer completely unshielded coils, but that requires a balanced Rx front end. Most builds around here are with unbalanced front end that has a benefit of lower noise, but at a cost of shielding. Shielding is a de-facto industry standard now.

[MaverickITA]

Some of my simulations show that shielding both Rx and Tx leads to less phase shift than shielding Rx alone. I prefer completely unshielded coils, but that requires a balanced Rx front end. Most builds around here are with unbalanced front end that has a benefit of lower noise, but at a cost of shielding. Shielding is a de-facto industry standard now.

Which software do you use to simulate?

[Davor]

LTspice, as most people here do.

[Koala]

I know that only RX coil need shield.
I am wrong?

Are there many differences in shielding also TX or it is exactly the same?
In which case is mandatory shield also TX?

At the moment many use graphite spray but the problem is the housing.
I am using one model that do not have something to close it under.
Therefore I prefer to shield coils directly with adesive aluminium tape connected to ground.

I wait your help...
Thanks.

I have tried many different ways of shielding with a space blanket and every one has failed.

cardboard plate covered in graphite works fine.

Never tried aluminum tape but if it's too thick you will loose sensitivity

[WM6]

Hi Koala
what mean "space blanket"?

[Koala]

Hi Koala
what mean "space blanket"?

http://www.firstaid.co.uk/HypaGuard-...q61RoC15Lw_wcB

One side is conductive with a aluminum coating. Not sure why I can not make it work. If you look on the IDX thread I have listed all the combination I have tried.

[MaverickITA]

I have tried many different ways of shielding with a space blanket and every one has failed.

cardboard plate covered in graphite works fine.

Never tried aluminum tape but if it's too thick you will loose sensitivity

I assure you that adesive aluminium tape work well, the one used from me is thin enough.
I compared before and after, I did not see significant differences.

[MaverickITA]

LTspice, as most people here do.

I do not like too much LTspice because its library is very limited.
It has only Linear products.

[Qiaozhi]

I do not like too much LTspice because its library is very limited.
It has only Linear products.

LTSpice is not limited to its own models. You can use external models from other vendors, the same as any other Spice derivative.

[MaverickITA]

LTSpice is not limited to its own models. You can use external models from other vendors, the same as any other Spice derivative.

I have used this simulator in the past but I have missed this opportunity.
I thinked was possible use only a new model created from zero or copied and modified from one already existing but instead there is this very interesting feature.
Good news, LTspice is very easy to use.

But I do not found a way to give in input "white noise" for example instead of a fixed sine frequency.
Do you know if exist this chance?

Thank you.

[Davor]

What for?
There is no true white noise generator built in, but there are some approximations. There are very few uses for noise source in spice sims.
If you need to analyse frequency response, you'll use AC analysis, and if you need noise performance, it is also there. Distortion calculation is also there.
True white noise is very difficult to come by due to its rich dynamic span and the amplitude distribution, so whatever simulator offers it must also revert to some sort of approximation.
I have a few such noise sources somewhere in archives, but after I learned what they do, I never needed them again.

[Qiaozhi]

But I do not found a way to give in input "white noise" for example instead of a fixed sine frequency.
Do you know if exist this chance?

Actually, LTSpice is able to generate both random and white noise in the time domain.
You can use either an arbitrary voltage or current source (B element) to inject a signal into your circuit using either the random or white functions,
Please see the attached LTSpice User Manual.

[MaverickITA]

What for?
There is no true white noise generator built in, but there are some approximations. There are very few uses for noise source in spice sims.
If you need to analyse frequency response, you'll use AC analysis, and if you need noise performance, it is also there. Distortion calculation is also there.
True white noise is very difficult to come by due to its rich dynamic span and the amplitude distribution, so whatever simulator offers it must also revert to some sort of approximation.
I have a few such noise sources somewhere in archives, but after I learned what they do, I never needed them again.

I need to study the user manual of this software.
However, it was for analyse frequency response but it is correct AC analysis.
Thank you.

[MaverickITA]

Actually, LTSpice is able to generate both random and white noise in the time domain.
You can use either an arbitrary voltage or current source (B element) to inject a signal into your circuit using either the random or white functions,
Please see the attached LTSpice User Manual.

Thank you, I must study it before to continue...