From: "Clemens Paul" <cpaul@gmx.net>
To: <rsgb_lf_group@blacksheep.org>
References: <CAKvcm2cJtu=F5yHvR53Vkvf5bb8J1BQVKi9U4g-kupA+6i1=UA@mail.gmail.com> <CAKvcm2e-MyjDe=SJ8K0HhYczVtYCc0n0cSnaZeRHWLSa_TTgwQ@mail.gmail.com> <E97A866FD0F342129E8FE5B0AF47C2D0@Clemens0811> <CAKvcm2fvcg19OdFCDOf_1HJ8QMb80gfZ6b9vjBjn=2e=N_q5tw@mail.gmail.com>
In-Reply-To: <CAKvcm2fvcg19OdFCDOf_1HJ8QMb80gfZ6b9vjBjn=2e=N_q5tw@mail.gmail.com>
Date: Sat, 12 Jan 2019 21:23:07 +0100
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Subject: RE: LF: RE: Re: a lot of ferrite
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Hi Dimitris, 

>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...

The cross section of the rods or equivalent toroid is 2cm x 10cm.
If you take 10cm as height the ring is 2cm thick.
Hence the OD/ID difference is indeed 2cm not 4cm...

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 8:55 PM
>To: rsgb_lf_group@blacksheep.org
>Subject: Re: LF: RE: Re: a lot of ferrite
>
>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
>> >
>>
>>
>