Threshold Pot doesn't work

[eduardo1979]

Hi h9361.
Why don't you try implementing the TX circuit from the Fisher CZ5? I think it would be a good starting point.

[Carl-NC]

Please check attached. Do you think the bandpass (from 15Khz to 107Khz) is true?

Again, I don't know without simulating it. It will also make a difference whether L3 and L4 are coupled (also polarity) or decoupled.

[h9361]

Something like this maybe...

thanks

[h9361]

here is a free online tool for desiging LC filters ( low, band, high )

https://markimicrowave.com/technical...r-design-tool/

It can export the design in ltspice so you can sim it.

Thanks

[h9361]

I suspect it's not so simple, and I don't know without either building the circuit or simulating it. But you can do that, so I suggest you put it in LTSpice and find out what happens.

Please check attached. Do you think the bandpass (from 15Khz to 107Khz) is true?

[nejdet]

Something like this maybe...

[moodz]

here is a free online tool for desiging LC filters ( low, band, high )

https://markimicrowave.com/technical...r-design-tool/

It can export the design in ltspice so you can sim it.

[h9361]

I suspect it's not so simple, and I don't know without either building the circuit or simulating it. But you can do that, so I suggest you put it in LTSpice and find out what happens.

I have not worked with LTSpice. I usually use Porteous software for simulation, i will try to simulate it.
I have a another question. Please see again schematic of #618, do you have any suggestion for making a bandpass filter?
For exp, i want to only receive from 5Khz to 30Khz range. Suppose that we have two coils ( inductor) and two resonance capacitors.
First Tank is tuned to 5Khz and second is tuned to 30Khz. But i do not know how to draw a bandpass for this range via this coils and resonance capacitors.
Thanks

[Carl-NC]

I suspect it's not so simple, and I don't know without either building the circuit or simulating it. But you can do that, so I suggest you put it in LTSpice and find out what happens.

[h9361]

Any coil can do that as long as you don't resonate it with a cap.

I want to receive only two or three frequencies at the same time.
Please see attached, this is named as coupling mode (Tap).



A friend told me old radio used this method.
I have a question, which of the following is true?

Calculation 1
F1=(L1+L2+L3)+C1
F2=(L1+L2)+C2
F3=L1+C3

Or
Calculation 2
F1=(L1+L2+L3)+C1
F2=(L2+L3)+C2
F3=L3+C3

[Carl-NC]

Any coil can do that as long as you don't resonate it with a cap.

[h9361]

Are you wanting an RX coil that can receive 2 frequencies, or a TX coil that can generate 2 frequencies? What you show cannot oscillate, it has no feedback mechanism. Otherwise, I have no experience trying to do what I think you want to do.

Only receiving RX without any TX.

[Carl-NC]

This model can receive two frequencies Simultaneously.
Is it possible to tell me your opinion?

Are you wanting an RX coil that can receive 2 frequencies, or a TX coil that can generate 2 frequencies? What you show cannot oscillate, it has no feedback mechanism. Otherwise, I have no experience trying to do what I think you want to do.

[h9361]

what are the frequencies ?

KHz range,
exp, 30 and 70Khz.

[pito]