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---
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title: Homebrew common mode choke
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summary: |
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A simple and quite tiny common mode choke that I built for my
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portable operations.
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date: 2023-10-26T13:36:26+02:00
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#lastmod:
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#categories:
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#- amateur-radio
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#- computerstuff
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#tags:
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showBreadcrumbs: true
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# showDate: false
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showReadingTime: false
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showWordCount: false
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# showPagination: false
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# feed_exclude: true
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# site_exclude: true
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draft: true
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---
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So this is basically a 140-43 toroid with 9 turns of RG174 connected to
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BNC connectors.
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It works very well and I have made two measurements recently.
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{{< figure src="logmag_through.png" caption="The maximum loss is on 10m around 0.2dB" >}}
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{{< figure src="logmag_outer.png" caption="It attenuates common mode current with more than 20dB" >}}
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I find this okay for now but I still wonder if this can be made any better
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(maybe 30dB attenuation?). Would I benefit from even more attenuation?
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I will probably find out on another day.
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