- 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 <noreply@anthropic.com>
134 lines
4.5 KiB
Markdown
134 lines
4.5 KiB
Markdown
## Skyddsavstånd: fjärrfältsberäkning (utan kabeldämpning)
|
|
|
|
* För fasta amatörradioanläggningar bestäms skyddsavståndet med fjärrfältsformeln
|
|
|
|
<fragment>
|
|
$d=\dfrac{\sqrt{30\,\Omega\cdot P_A\cdot G_i}}{E}$
|
|
</fragment>
|
|
|
|
--- style="font-size: 0.7em;"
|
|
#### Tilläggsinformation om moduleringsmetoder vid beräkning av skyddsavstånd
|
|
|
|
* Spetseffekten (PEP) omvandlas till medeleffekt med en faktor beroende på moduleringsmetod; medeleffekten används i fjärrfältsformeln
|
|
* De flesta moduleringsmetoder har här faktorn $\num{1}$
|
|
* ATV: faktor $\num{0,38}$
|
|
|
|
<note>
|
|
EN 50413; för amatörradio är endast ATV med $\num{0,38}$ och SATV med $\num{0,54}$ relevanta
|
|
</note>
|
|
|
|
--- style="font-size: smaller;"
|
|
#### Räkneexempel 1
|
|
<left>
|
|
* givet: $E = \qty{28}{\volt\per\meter}$
|
|
* givet: $P_S = P_A = \qty{100}{\watt}$
|
|
</left>
|
|
<right>
|
|
* givet: $G_i = 1,64$
|
|
* sökt: $d$
|
|
</right>
|
|
|
|
<fragment>
|
|
$\begin{split}E &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_A \cdot G_i}}{d}\\ \Rightarrow d &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_A \cdot G_i}}{E}\\ &= \frac{\sqrt{\qty{30}{\ohm} \cdot \qty{100}{\watt} \cdot 1,64}}{\qty{28}{\volt\per\meter}}\\ &\approx \qty{2,5}{\meter}\end{split}$
|
|
</fragment>
|
|
|
|
---
|
|
## Skyddsavstånd: hänsyn till kabeldämpning
|
|
* Först beräknas den ekvivalent isotropiskt utstrålade effekten (EIRP)
|
|
|
|
<fragment>
|
|
$P_\text{EIRP} = P_S\cdot10^{\frac{g_d - a + \qty{2,15}{\dB}}{\qty{10}{\dB}}}$
|
|
</fragment>
|
|
|
|
--- style="font-size: smaller;"
|
|
#### Räkneexempel 2
|
|
<left>
|
|
* givet: $E = \qty{28}{\volt\per\meter}$
|
|
* givet: $P_S = \qty{300}{\watt}$
|
|
* givet: $a = \qty{0,5}{\dB}$
|
|
</left>
|
|
<right>
|
|
* givet: $g_d = \qty{0}{\dBd}$
|
|
* sökt: $d$
|
|
</right>
|
|
|
|
<fragment>
|
|
<left>
|
|
$\begin{split}P_{EIRP} &= P_S \cdot 10^{\frac{g_d -a + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &= \qty{300}{\watt} \cdot 10^{\frac{\qty{0}{\dBd} - \qty{0,5}{\dB} + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &\approx \qty{438,7}{\watt}\end{split}$
|
|
</left>
|
|
</fragment>
|
|
<fragment>
|
|
<right>
|
|
$\begin{split}E &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{d}\\ \Rightarrow d &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{E}\\ &= \frac{\sqrt{\qty{30}{\ohm} \cdot \qty{438,7}{\watt}}}{\qty{28}{\volt\per\meter}}\\ &\approx \qty{4,10}{\meter}\end{split}$
|
|
</right>
|
|
</fragment>
|
|
|
|
--- style="font-size: smaller;"
|
|
#### Räkneexempel 3
|
|
<left>
|
|
* givet: $E = \qty{28}{\volt\per\meter}$
|
|
* givet: $P_S = \qty{700}{\watt}$
|
|
* givet: $a = \qty{0,5}{\dB}$
|
|
</left>
|
|
<right>
|
|
* givet: $g_d = \qty{0}{\dBd}$
|
|
* sökt: $d$
|
|
</right>
|
|
|
|
<fragment>
|
|
<left>
|
|
$\begin{split}P_{EIRP} &= P_S \cdot 10^{\frac{g_d -a + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &= \qty{700}{\watt} \cdot 10^{\frac{\qty{0}{\dBd} - \qty{0,5}{\dB} + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &\approx \qty{1023,5}{\watt}\end{split}$
|
|
</left>
|
|
</fragment>
|
|
<fragment>
|
|
<right>
|
|
$\begin{split}E &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{d}\\ \Rightarrow d &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{E}\\ &= \frac{\sqrt{\qty{30}{\ohm} \cdot \qty{1023,5}{\watt}}}{\qty{28}{\volt\per\meter}}\\ &\approx \qty{6,26}{\meter}\end{split}$
|
|
</right>
|
|
</fragment>
|
|
|
|
--- style="font-size: smaller;"
|
|
#### Räkneexempel 4
|
|
<left>
|
|
* givet: $E = \qty{28}{\volt\per\meter}$
|
|
* givet: $P_S = \qty{75}{\watt}$
|
|
* givet: $a = \qty{1,5}{\dB}$
|
|
</left>
|
|
<right>
|
|
* givet: $g_d = \qty{11,5}{\dBd}$
|
|
* sökt: $d$
|
|
</right>
|
|
|
|
<fragment>
|
|
<left>
|
|
$\begin{split}P_{EIRP} &= P_S \cdot 10^{\frac{g_d -a + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &= \qty{75}{\watt} \cdot 10^{\frac{\qty{11,5}{\dBd} - \qty{1,5}{\dB} + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &\approx \qty{1230,4}{\watt}\end{split}$
|
|
</left>
|
|
</fragment>
|
|
<fragment>
|
|
<right>
|
|
$\begin{split}E &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{d}\\ \Rightarrow d &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{E}\\ &= \frac{\sqrt{\qty{30}{\ohm} \cdot \qty{1230,4}{\watt}}}{\qty{28}{\volt\per\meter}}\\ &\approx \qty{6,86}{\meter}\end{split}$
|
|
</right>
|
|
</fragment>
|
|
|
|
--- style="font-size: smaller;"
|
|
#### Räkneexempel 5
|
|
<left>
|
|
* givet: $E = \qty{61}{\volt\per\meter}$
|
|
* givet: $P_S = \qty{40}{\watt}$
|
|
* givet: $a = \qty{2}{\dB}$
|
|
</left>
|
|
<right>
|
|
* givet: $g_d = \qty{18}{\dBd}$
|
|
* sökt: $d$
|
|
</right>
|
|
|
|
<fragment>
|
|
<left>
|
|
$\begin{split}P_{EIRP} &= P_S \cdot 10^{\frac{g_d -a + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &= \qty{40}{\watt} \cdot 10^{\frac{\qty{18}{\dBd} - \qty{2}{\dB} + \qty{2,15}{\dB}}{\qty{10}{\dB}}}\\ &\approx \qty{2612,5}{\watt}\end{split}$
|
|
</left>
|
|
</fragment>
|
|
<fragment>
|
|
<right>
|
|
$\begin{split}E &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{d}\\ \Rightarrow d &= \frac{\sqrt{\qty{30}{\ohm} \cdot P_{EIRP}}}{E}\\ &= \frac{\sqrt{\qty{30}{\ohm} \cdot \qty{2612,5}{\watt}}}{\qty{61}{\volt\per\meter}}\\ &\approx \qty{4,6}{\meter}\end{split}$
|
|
</right>
|
|
</fragment>
|