RE: VLF: T106-52 cores on VLF

["Clemens Paul" <cpaul@gmx.net>]

Hi Tom,

>I think the problem are the airgaps between the cores.

I have measured a big air core coil of approx. 3.37mH
- once w/o ferrites inside
- once with two identical ferrite cores (µi about 125) spaced by 2cm
- once with one core of the same type and dimensions exept
  its height which is exactly twice of the cores above.

See screenshot and picture.
The red trace is w/o ferrite core(s),
the green trace is with the two ferrite cores spaced apart
the blue trace on top is with the double height core.

This is not exactly representing Stefan's coil because the ferrite cores are 
much smaller in diameter than the coil but one can see a trend:
Eliminating the air gap between the cores has very little effect.

73
Clemens
DL4RAJ 

>-----Original Message-----
>From: owner-rsgb_lf_group@blacksheep.org 
>[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of DK1IS
>Sent: Thursday, April 28, 2016 11:09 AM
>To: rsgb_lf_group@blacksheep.org
>Subject: Re: VLF: T106-52 cores on VLF
>
>Hi Stefan,

Coil_plot 3.37mH.JPG
Description: JPEG image

Coil_3.37mH.JPG
Description: JPEG image