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Re: Akula, Ruslan, Stalker, device discussion and replications. « Reply #157 on: 2023-06-12, 11:30:15 »
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Quote from: Apecore on 2023-06-11, 21:44:32
Hi Itsu,
I' m not aware in how doing a inductance measurement at 10khz.
I'm using a Chinees board to plug in a coil or cap and it delivers a value.
Let me know how the 10khz method works.
My interpretation about the grenade config is that it has to absorb electrostatic energy from the antenna.
We need a field in the grenade to interact with antenna..... how this is being done we need to find out.
Inductor playes a part in this.I guess. How? We have to find out.
But in my opinion we need some excitement of standing wave in the grenade together with inductor field coöperation.
So thats why my journey starts with the magnetic field interpretation at 2Mhz
Men could argue that tbe 28turn coil could disrupt also something inside the grenade with its squarewave's.
But enough speculating..., hands-on.... we need a sort of test/ discovery plan.
Ape
Ape,
i have an LCR meter Agilent UC1733C (
https://www.keysight.com/us/en/product/U1733C/handheld-lcr-meter-100-hz-120-hz-1-khz-10-khz100-khz.html) which measures the inductance (among other things)
of a coil on several different selectable frequencies (100Hz, 120Hz, 1KHz, 10kHz and 100kHz).
As we run the Grenade between 10 to 25kHz, i selected the 10kHz range which measured the mentioned 150uH.
Therefor i always mention the Inductance at a certain frequency (150uH @ 10kHz) as the inductance varies with frequency.
To show how the inductance of a coil (in this case my Grenade) can vary by frequency i use my nanoVNA to give me the inductance value over a frequency range like here (from my post #39):
It shows at the 10kHz range (starting frequency of my nanoVNA) the same 150uH as the LCR meter, but then starts to deviate when increasing the frequency until resonance after which the grenade starts to show negative inductances meaning capacitance.
If my LCR meter would be able to measure at say 3.45MHz (marker 3 in the graph) it would show an inductance of -43.3uH and when in "auto mode" switches over to capacitance.
Itsu
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Grenade inductance versus frequency.png
* Grenade inductance versus frequency.png (155.1 kB, 1403x484 - viewed 139 times.)