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From: Dimitrios Tsifakis <dtsifakis@gmail.com>
Date: Sun, 13 Jan 2019 06:55:10 +1100
Message-ID: <CAKvcm2fvcg19OdFCDOf_1HJ8QMb80gfZ6b9vjBjn=2e=N_q5tw@mail.gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: RE: Re: a lot of ferrite
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Hi Clemens,

the mistake I made the first time was that I incorrectly set the ID/OD
difference of the equivalent ring to be 2 cm instead of 4...

73, Dimitris VK2COW

Στις Κυρ, 13 Ιαν 2019 στις 1:20 π.μ., ο/η Clemens Paul <cpaul@gmx.net> έγραψε:
>
>  Hi Dimitris,
>
> >Minor correction, the calculated relative permeability should be about
> >500,
>
> I've made a calculation based on your data with the mini ring-core calculator
> and it says µ = 1070 and AL = 937.5nH /N^2
>
> So your first calculation seems to be right.
>
> 73
> Clemens
> DL4RAJ
>
>
>
> >-----Original Message-----
> >From: owner-rsgb_lf_group@blacksheep.org
> >[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of
> >Dimitrios Tsifakis
> >Sent: Saturday, January 12, 2019 5:03 AM
> >To: rsgb_lf_group@blacksheep.org
> >Subject: LF: Re: a lot of ferrite
> >
> >Minor correction, the calculated relative permeability should be about
> >500, I made a mistake in the initial calculation. I just discover why
> >they call it initial permeability (bad joke) :-)
> >
> >73, Dimitris VK2COW
> >
> >Στις Σάβ, 12 Ιαν 2019 στις 2:48 μ.μ., ο/η Dimitrios Tsifakis
> ><dtsifakis@gmail.com> έγραψε:
> >>
> >> Hi LF group,
> >>
> >> I have managed to acquire a few very large ferrite rods (36
> >cm x 10 cm
> >> x 2 cm). The material is unknown but I managed to form a square
> >> 'toroid' with four of them (they are heavy so gravity was enough to
> >> keep everything in place for a measurement) and I measured
> >about 15 uH
> >> for 4 turns at 0.1 MHz, which if I have done the calculations
> >> correctly implies a relative permeability of about 1000.
> >>
> >> The R of the impedance of the square loop was low (<0.2 ohm) at 0.1
> >> MHz and it increased fast with frequency (170 ohm at 5 MHz!).
> >>
> >> The question is, what LF/VLF experiment would you do if you
> >had half a
> >> dozen of these rods?
> >>
> >> 73, Dimitris VK2COW
> >
> >
> >---
> >Diese E-Mail wurde von AVG auf Viren geprüft.
> >http://www.avg.com
> >
>
>