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]>
103 lines
3.4 KiB
Markdown
103 lines
3.4 KiB
Markdown
## Matarantenner i parabolreflektorn
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<left>
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[picture:850:a_parabolspiegel_schnitt:Snitt genom en parabolreflektor med antenn]
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</left>
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<right>
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* I punkten framför parabolreflektorn placeras matarantennen
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* Helixantenner, som ger cirkulär polarisation, passar särskilt bra i mikrovågsområdet
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</right>
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---
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## Hornantenner och vågledare
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<left>
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Bild på en hornantenn följer
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</left>
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<right>
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* Hornantenner kan matas med en vågledare
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* I vågledare, alltså metallrör, leds mikrovågsenergin genom reflektion mot ytterväggarna
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</right>
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---
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## Vågledare i detalj
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* Vågledare leder mikrovågor genom att reflektera dem mot sina metalliska ytterväggar
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* Därmed kommer vågen fram till ett horn, ur vilket den strålas ut eller från vilket den matas in i vågledaren
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---
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## Vinst hos en parabolreflektor
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$g_i = 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot d}{\lambda}\right)^2 \cdot \eta\right)}\unit{\dBi}$
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* Beräkning med formeln i formelsamlingen
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* Beror på diametern
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* Vanligtvis mycket hög vinst
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---
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#### Räkneexempel
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<left>
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* givet: $d = \qty{30}{\centi\meter}$
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* givet: $\eta_{eff} = 1$
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</left>
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<right>
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* givet: $f = \qty{5,7}{\giga\hertz}$
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* sökt: $g_i$
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</right>
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<fragment>
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$\lambda = \frac{c}{f} = \frac{\qty{3\cdot 10^8}{\meter\per\second}}{\qty{5,7}{\giga\hertz}} = \qty{0,053}{\meter}$
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</fragment>
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<fragment>
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$\begin{split}g_i &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot d}{\lambda}\right)^2 \cdot \eta\right)}\unit{\dBi}\\ &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot \qty{0,3}{\meter}}{\qty{0,053}{\meter}}\right)^2 \cdot 1\right)} \unit{\dBi}\\ &= \qty{25,1}{\dBi}\end{split}$
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</fragment>
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---
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#### Räkneexempel
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<left>
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* givet: $d = \qty{80}{\centi\meter}$
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* givet: $\eta_{eff} = 1$
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</left>
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<right>
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* givet: $f = \qty{5,7}{\giga\hertz}$
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* sökt: $g_i$
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</right>
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<fragment>
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$\lambda = \frac{c}{f} = \frac{\qty{3\cdot 10^8}{\meter\per\second}}{\qty{5,7}{\giga\hertz}} = \qty{0,053}{\meter}$
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</fragment>
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<fragment>
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$\begin{split}g_i &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot d}{\lambda}\right)^2 \cdot \eta\right)}\unit{\dBi}\\ &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot \qty{0,8}{\meter}}{\qty{0,053}{\meter}}\right)^2 \cdot 1\right)}\unit{\dBi}\\ &= \qty{33,6}{\dBi}\end{split}$
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</fragment>
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---
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#### Räkneexempel
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<left>
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* givet: $d = \qty{80}{\centi\meter}$
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* givet: $\eta_{eff} = 1$
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</left>
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<right>
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* givet: $f = \qty{10,4}{\giga\hertz}$
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* sökt: $g_i$
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</right>
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<fragment>
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$\lambda = \frac{c}{f} = \frac{\qty{3\cdot 10^8}{\meter\per\second}}{\qty{10,4}{\giga\hertz}} = \qty{0,029}{\meter}$
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</fragment>
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<fragment>
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$\begin{split}g_i &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot d}{\lambda}\right)^2 \cdot \eta\right)}\unit{\dBi}\\ &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot \qty{0,8}{\meter}}{\qty{0,029}{\meter}}\right)^2 \cdot 1\right)}\unit{\dBi}\\ &= \qty{38,8}{\dBi}\end{split}$
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</fragment>
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---
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#### Räkneexempel
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<left>
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* givet: $d = \qty{120}{\centi\meter}$
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* givet: $\eta_{eff} = 1$
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</left>
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<right>
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* givet: $f = \qty{10,4}{\giga\hertz}$
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* sökt: $g_i$
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</right>
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<fragment>
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$\lambda = \frac{c}{f} = \frac{\qty{3\cdot 10^8}{\meter\per\second}}{\qty{10,4}{\giga\hertz}} = \qty{0,029}{\meter}$
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</fragment>
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<fragment>
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$\begin{split}g_i &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot d}{\lambda}\right)^2 \cdot \eta\right)}\unit{\dBi}\\ &= 10 \cdot \log_{10}{\left(\left(\frac{\pi \cdot \qty{1,2}{\meter}}{\qty{0,029}{\meter}}\right)^2 \cdot 1\right)}\unit{\dBi}\\ &= \qty{42,3}{\dBi}\end{split}$
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</fragment>
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