Re: VLF: T106-52 cores on VLF

To:	[email protected]
Subject:	Re: VLF: T106-52 cores on VLF
From:	DK1IS <[email protected]>
Date:	Thu, 28 Apr 2016 11:09:14 +0200
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Hi Stefan,

I think the problem are the airgaps between the cores. Perhaps you´llget a little better result if you grind down the coatings at the innerfront ends of the cores. Although its nearly impossible to get reallysmooth fitting surfaces in this way there should be some improvement.Due to the low conductivity of the core material the loss of coatingshouldn´t have appreciable disadvantages.


73,
Tom, DK1IS
- still working at his remote garage RX site.


Am 27.04.2016 um 20:20 schrieb DK7FC:

Hi VLF,
I've done a quick experiment with the T106-52 cores which could givesome more ideas regarding these cores for a compact VLF coil.
I wound a coil with 0.5mm enameled cu wire, 85 turns at 33mm diameter.Inside the coil there are 5 of these cores stacked on another. Inparallel there is a suitable C of 1 uF.
https://dl.dropboxusercontent.com/u/19882028/VLF/20160427_195530.jpg
The resonance was found at 7.49 kHz. The 3 dB bandwidth is (7.64-7.36)kHz = 280 Hz. Q = 27. L = 452 uH.Without the cores inside, the resonance frequency rises to 14.54 kHzand the bandwidth is (15.12-14.07) kHz = 1.05 kHz. Q = 14. L = 120 uH.
Hmm, so in this configuration, the effective µr (ur) seems to be just3.75! :-/That means i still need half of the number of turns for a single layerVLF transmit coil?!?
73, Stefan


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Re: VLF: EbNaut transmission on 8270.1 Hz again, (continued) Re: VLF: EbNaut transmission on 8270.1 Hz again, Paul Nicholson Re: VLF: EbNaut transmission on 8270.1 Hz again, Paul Nicholson Re: VLF: EbNaut QRN and propagation considerations, DK7FC Re: VLF: EbNaut QRN and propagation considerations, Paul Nicholson VLF: A single turn RX loop for VLF, DK7FC Re: VLF: A single turn RX loop for VLF, Wolfgang Büscher Re: VLF: A single turn RX loop for VLF, Lubos Re: VLF: A single turn RX loop for VLF, Paul Nicholson Re: VLF: A single turn RX loop for VLF, DK7FC VLF: T106-52 cores on VLF, DK7FC Re: VLF: T106-52 cores on VLF, DK1IS <= RE: VLF: T106-52 cores on VLF, Clemens Paul Re: VLF: T106-52 cores on VLF, DK1IS Re: VLF: T106-52 cores on VLF, continued..., DK7FC Re: VLF: T106-52 cores on VLF, continued, thoughts..., DK7FC Re: VLF: T106-52 cores on VLF, continued, thoughts..., Rik Strobbe Re: VLF: T106-52 cores on VLF, continued, thoughts..., DK7FC Re: VLF: T106-52 cores on VLF, continued, thoughts..., Lawrence Galea Re: VLF: T106-52 cores on VLF, continued, thoughts..., Rik Strobbe Re: VLF: T106-52 cores on VLF, continued, thoughts..., DK7FC Re: VLF: T106-52 cores on VLF, the best coil body, DK7FC

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