SuperminarenandClaude Sonnet 5.5
f7fa8cfbc1
- Sections and slides rewritten in Swedish; German law and institutions replaced by Swedish/CEPT/ITU equivalents (PTS, SSA, PTSFS 2025:1, SSMFS 2008:18), unverified statements marked "% TODO VERIFY" - New toc: INSTEG, HAREC, UPPGRADERING; section idents are Swedish (see ident-map.tsv) - Exam-question tags, BNetzA question pool, solutions and the German SWL course removed - Static pages, snippets, applets, READMEs and image alt-texts translated - TikZ labels translated; SVG drawings regenerated (drawing 689 still fails to build upstream: it references a missing photo) - Changed from the original: not endorsed by DARC e.V., SSA or PTS Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
51 lines
1.8 KiB
Markdown
51 lines
1.8 KiB
Markdown
* Våglängden $\lambda$ i fritt rum hänger ihop med frekvensen $f$ via ljushastigheten $c_0$
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* Fritt rum betyder: vakuum, luft
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* Ljushastighet $c_0 = \qty{299792458}{\meter\per\second}$
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* I amatörradio räknar vi med $c = \qty{3e8}{\meter\per\second}$
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$c = f\cdot \lambda \quad f = \dfrac{c}{\lambda} \quad \lambda = \dfrac{c}{f}$
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---
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## Förenkling
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$f = \dfrac{c}{\lambda} \quad \lambda = \dfrac{c}{f}$
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$f[[\unit{\mega\hertz}]] \approx \dfrac{300}{\lambda[[\unit{\meter}]]} \quad \lambda[[\unit{\meter}]] \approx \dfrac{300}{f[[\unit{\mega\hertz}]]}$
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* Försök alltid först själv hitta lösningen
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---
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* $\qty{80}{\meter}$-bandet $\approx \qtyrange{3,5}{3,8}{\mega\hertz}$
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$f[[\unit{\mega\hertz}]] = \frac{300}{80} = 3,75$
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---
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* Sätt alltid in värden i grundenheter, räkna vid behov om (t.ex. mm → m)
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$\qty{30}{\milli\meter} = \qty{3}{\centi\meter} = \qty{0,03}{\meter}$
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$f[[\unit{\mega\hertz}]] = \frac{300}{0,03} = \frac{300 \cdot 100}{3} = \num{10000}$
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$f = \qty{10}{\giga\hertz}$, eftersom $\qty{1}{\giga\hertz} = \qty{1000}{\mega\hertz}$
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---
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$\qty{10}{\centi\meter} = \qty{0,1}{\meter}$
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$f[[\unit{\mega\hertz}]]=\frac{300}{0,1}=3000$
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$\qty{3}{\giga\hertz}$, eftersom $\qty{1}{\giga\hertz} = \qty{1000}{\mega\hertz}$
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---
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* $\qty{160}{\meter}$-bandet $\approx \qtyrange{1,8}{2}{\mega\hertz}$
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* $\qty{1,84}{\mega\hertz}$ ligger däri → $\qty{163}{\meter}$
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* går att uppskatta utan räkning om man kan bandgränserna
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---
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* $\qty{15}{\meter}$-bandet $\approx \qtyrange{21}{21,45}{\mega\hertz}$ (namnet passar egentligen inte, $\qty{14}{\meter}$ vore bättre)
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$\lambda[[\unit{\meter}]] = \frac{300}{21} = 14,29$
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---
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* $\qty{10}{\meter}$-bandet $\approx \qtyrange{28}{29,7}{\mega\hertz}$ → $\qty{10,5}{\meter}$ för $\qty{28,5}{\mega\hertz}$
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* $\qty{9,49}{\meter}$ skulle motsvara $f > \qty{30}{\mega\hertz}$
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