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NoelM committed Apr 6, 2024
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24 changes: 24 additions & 0 deletions content/posts/efhw_antenna/elements/guying.scad
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echo(version=version());

inner_radius = 180/2;
outer_radius = 320/2;
holes_radius = 15;
holes_pos = (outer_radius+inner_radius)/2;
height = 50;

difference() {
cylinder(h=height, r=outer_radius, center=true);
cylinder(h=height+10, r=inner_radius, center=true);

translate([holes_pos, 0, 0])
cylinder(h=height+10, r=holes_radius, center= true);

translate([-holes_pos, 0, 0])
cylinder(h=height+10, r=holes_radius, center= true);

translate([0, holes_pos, 0])
cylinder(h=height+10, r=holes_radius, center= true);

translate([0, -holes_pos, 0])
cylinder(h=height+10, r=holes_radius, center= true);
}
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106 changes: 106 additions & 0 deletions content/posts/efhw_antenna/elements/isolators.scad
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// text_on_cube.scad - Example for text() usage in OpenSCAD

echo(version=version());

font = "Inter:style=Bold"; //["Liberation Sans", "Liberation Sans:style=Bold", "Liberation Sans:style=Italic", "Liberation Mono", "Liberation Serif"]

width = 120;
depth = 400;
height= 40;

letter_height = 3;
letter_size = 42;

module letter(l) {
// Use linear_extrude() to make the letters 3D objects as they
// are only 2D shapes when only using text()
color("gray")
linear_extrude(height = letter_height) {
text(l, size = letter_size, font = font, halign = "center", valign = "center", $fn = 16);
}
}

module insulator(x, band1, band2) {

translate([x, 0, 0])
union() {
difference() {
translate([width/2+75, 0, 0])
cube([150, 150, 40], center=true);

translate([width/2+75, 0, 0])
cylinder(h=50, r=35, center= true);
}
difference() {
union() {
cube([width, depth, height], center= true);

translate([0, 0, height/2])
rotate([0, 0, -90])
letter(band1);

translate([0, 0, -height/2])
rotate([0, -180, -90])
letter(band2);
}

translate([0,-150, 0])
cylinder(h=50, r=15, center= true);

translate([0,150, 0])
cylinder(h=50, r=15, center= true);
}
}
}

insulator(0, "15m \u25BA", "17m \u25BA");
insulator(350, "17m \u25BA", "20m \u25BA");
insulator(700, "20m \u25BA", "30m \u25BA");
insulator(1050, "30m \u25BA", "40m \u25BA");
insulator(1400, "40m \u25BA", "");



/*
o = cube_size / 2 - letter_height / 2;
module letter(l) {
// Use linear_extrude() to make the letters 3D objects as they
// are only 2D shapes when only using text()
linear_extrude(height = letter_height) {
text(l, size = letter_size, font = font, halign = "center", valign = "center", $fn = 16);
}
}
difference() {
union() {
color("gray") cube(cube_size, center = true);
translate([0, -o, 0]) rotate([90, 0, 0]) letter("C");
translate([o, 0, 0]) rotate([90, 0, 90]) letter("U");
translate([0, o, 0]) rotate([90, 0, 180]) letter("B");
translate([-o, 0, 0]) rotate([90, 0, -90]) letter("E");
}
// Put some symbols on top and bottom using symbols from the
// Unicode symbols table.
// (see https://en.wikipedia.org/wiki/Miscellaneous_Symbols)
//
// Note that depending on the font used, not all the symbols
// are actually available.
translate([0, 0, o]) letter("\u263A");
translate([0, 0, -o - letter_height]) letter("\u263C");
}
// Written in 2014 by Torsten Paul <Torsten.Paul@gmx.de>
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to the
// public domain worldwide. This software is distributed without any
// warranty.
//
// You should have received a copy of the CC0 Public Domain
// Dedication along with this software.
// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
*/
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17 changes: 17 additions & 0 deletions content/posts/efhw_antenna/elements/top.scad
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echo(version=version());

inner_radius = 180/2;
outer_radius = 320/2;
holes_radius = 20;
holes_pos = (outer_radius+inner_radius)/2;
height = 50;

difference() {
cube([120, 180, 50], center = true);

translate([0, 30, 0])
cylinder(h=60, r=35, center=true);

translate([0, -90+40, 0])
cylinder(h=60, r=10, center=true);
}
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62 changes: 59 additions & 3 deletions content/posts/efhw_antenna/index.md
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Expand Up @@ -51,7 +51,7 @@ $$
\sqrt{\frac{P_E \cdot Z_E}{P_S \cdot Z_S}} = \frac{N_E}{N_S}
$$

On suppose notre transformateur parfait, dans ces conditions les puissances d'entrée et de sorties
On suppose notre transformateur parfait, dans ces conditions les puissances d'entrée et de sortie
sont égales \(P_E = P_S\) et l'on retrouve le rapport des impédances ci-dessus. CQFD !

En conclusion pour des rapports d'impédances entre 100:1 et 50:1, il nous faudra des transformateurs entre 10:1 et 7:1
Expand All @@ -69,12 +69,12 @@ $$
comme exprimé par Steve Steams, K6OIK.

Dans mon cas, pour une section 0.5 mm² le facteur se situe entre 0.97 et 0.98. La longueur des brins s'exprime de la manière
suivante :
suivante ([feuille de calcul ODS](elements/lengths.ods)) :
$$
l (m) = K \frac{150}{f (MHz)} \,.
$$

| Band | Center (MHz) | λ/2 (m) | K λ/2 (m) | Sections (m)
| Bande | Centre (MHz) | λ/2 (m) | l (m) | Sections (m)
| -----|--------------|---------|-----------|--------------
| 15m | 21.2 |7.08 | 6.86 | 6.86
| 17m | 18.118 |8.28 | 8.03 | 1.17
Expand All @@ -83,5 +83,61 @@ $$
| 40m | 7.1 |21.13 | 20.49 | 6.12


### Contrepoids

Pour la longueur du contrepoids, le plus simple a été de suivre l'étude détaillée de Steves Yates, AA5TB[^1].
Il montre qu'un contrepoids de 0.05λ est purement resistif, pas de composante complexe, c'est à dire réactive.
Je vais donc partir sur ces dimenssions :

| Bande | Centre (MHz) | 0.05λ (m) | Sections (m)
| -----|----------|---------|--------------
| 15m | 21.2 | 0.71 | 0.71
| 17m | 18.118 | 0.83 | 0.12
| 20m | 14.15 | 1.06 | 0.23
| 30m | 10.125 | 1.48 | 0.42
| 40m | 7.1 | 2.11 | 0.63


### Design simplifié

{{<hint>}}
Pour l'instant, nous nous concentrerons que sur l'antenne au design complet. Celle ci sera pour une prochaine fois !
{{</hint>}}

Selon plusieurs posts à droite à gauche et même certaines antennes comme celle de [DL2MAN](https://dl2man.de/portable-efhw-for-40-20-15-10m/)
un simple brin rayonnant de 20.5 mètres ferait l'affaire pour 4 bandes.

J'imagine pour cela dun design simplifié basé sur deux sections :
* l'une résonnant à 40 mètres, et théoriquement 20
* l''autre résonnant à 30 mètres, et théoriquement à 15 et 17

Ce qui nous donnerait les dimenssions suivantes :

| Bande | l (m) | Sections (m)
| ----------|-----------|---------
| 30-17-15m | 14.37 | 14.37
| 40-20m | 20.49 | 6.12

## Matériel

Entre chacune des sections de l'antenne il me faut de petits isolateurs qui permettent d'isoler
ou non les brins entre eux. Pour ce faire, j'ai créé ces éléments avec [OpenSCAD](https://openscad.org/)
pour les imprimer en 3D. Ne me demandez pas comment et avec quelle matière ils ont été imprimés, c'est
un ami qui l'a fait pour moi.

![Isolateurs modèles 3D](images/insulators.png)
![Isolateurs imprimés](images/IMG_1230.jpg)


### Liste

* Isolateurs, source [OpenSCAD](elements/isolators.scad) et [STL](elements/isolators.stl)
* Fil multibrin, 0.5 mm², usage en QRP dans mon cas 5W (Yaesu FT-817)
* Cosses à sertir, [exemple](https://www.amazon.fr/dp/B0CFQPBJT8?psc=1&ref=ppx_yo2ov_dt_b_product_details)

## Tests

À venir !

[^1]: [The End Fed Half Wave Antenna, _Steve Yates AA5TB_](https://www.aa5tb.com/efha.html)
[^2]: Amateur Radio Handbook, ARRL, Edition 100, Sec. 21.1.7
4 changes: 2 additions & 2 deletions public/404.html
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<!DOCTYPE html>
<html><head>
<html><head><script src="/livereload.js?mindelay=10&amp;v=2&amp;port=1313&amp;path=livereload" data-no-instant defer></script>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
Expand All @@ -20,7 +20,7 @@
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<link rel="canonical" href="https://noelmrtn.fr/404.html" />
<link rel="canonical" href="http://localhost:1313/404.html" />
<link rel="stylesheet" href="/css/style.css">
</head><body><header>
<span style="font-size: 1.5em;">noelmrtn</span><br>
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4 changes: 2 additions & 2 deletions public/categories/index.xml
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<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
<channel>
<title>Categories on noelmrtn</title>
<link>https://noelmrtn.fr/categories/</link>
<link>http://localhost:1313/categories/</link>
<description>Recent content in Categories on noelmrtn</description>
<generator>Hugo -- gohugo.io</generator>
<language>en-us</language>
<atom:link href="https://noelmrtn.fr/categories/index.xml" rel="self" type="application/rss+xml" />
<atom:link href="http://localhost:1313/categories/index.xml" rel="self" type="application/rss+xml" />
</channel>
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12 changes: 6 additions & 6 deletions public/index.html
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@@ -1,6 +1,6 @@
<!DOCTYPE html>
<html><head>
<meta name="generator" content="Hugo 0.124.1">
<meta name="generator" content="Hugo 0.124.1"><script src="/livereload.js?mindelay=10&amp;v=2&amp;port=1313&amp;path=livereload" data-no-instant defer></script>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
Expand All @@ -21,7 +21,7 @@
</script>


<link rel="canonical" href="https://noelmrtn.fr/" />
<link rel="canonical" href="http://localhost:1313/" />
<link rel="stylesheet" href="/css/style.css">
</head><body><header>
<span style="font-size: 1.5em;">noelmrtn</span><br>
Expand All @@ -44,19 +44,19 @@ <h1>Noël&#39;s Home</h1>
<h2>Articles</h2>
<ul id="posts">
<li>
<a href="https://noelmrtn.fr/posts/efhw_antenna/">Construction d&#39;une antenne long-fil EFHW multibande</a>
<a href="http://localhost:1313/posts/efhw_antenna/">Construction d&#39;une antenne long-fil EFHW multibande</a>
<small><time>2024-04-02</time></small>
</li>
<li>
<a href="https://noelmrtn.fr/posts/zig_threading/">Zig Threading Tutorial</a>
<a href="http://localhost:1313/posts/zig_threading/">Zig Threading Tutorial</a>
<small><time>2023-08-16</time></small>
</li>
<li>
<a href="https://noelmrtn.fr/posts/zig_and_c/">Prime Numbers Algorithm, in Zig and C</a>
<a href="http://localhost:1313/posts/zig_and_c/">Prime Numbers Algorithm, in Zig and C</a>
<small><time>2023-07-22</time></small>
</li>
<li>
<a href="https://noelmrtn.fr/posts/loop_antenna/">My Journey Building a Magnetic Loop Antenna</a>
<a href="http://localhost:1313/posts/loop_antenna/">My Journey Building a Magnetic Loop Antenna</a>
<small><time>2022-12-18</time></small>
</li>
</ul>
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<channel>
<title>Noël&#39;s Home on noelmrtn</title>
<link>https://noelmrtn.fr/</link>
<link>http://localhost:1313/</link>
<description>Recent content in Noël&#39;s Home on noelmrtn</description>
<generator>Hugo -- gohugo.io</generator>
<language>en-us</language>
<lastBuildDate>Tue, 02 Apr 2024 00:00:00 +0000</lastBuildDate>
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<item>
<title>Construction d&#39;une antenne long-fil EFHW multibande</title>
<link>https://noelmrtn.fr/posts/efhw_antenna/</link>
<link>http://localhost:1313/posts/efhw_antenna/</link>
<pubDate>Tue, 02 Apr 2024 00:00:00 +0000</pubDate>
<guid>https://noelmrtn.fr/posts/efhw_antenna/</guid>
<guid>http://localhost:1313/posts/efhw_antenna/</guid>
<description>Habitant en ville, il n&amp;rsquo;est pas simple de faire de la HF. Alors la majeure partie du temps j&amp;rsquo;opère en HF en portable avec mon Yaesu FT-817 et un mat SOTA beams de 7m. Quant à l&amp;rsquo;antenne, j&amp;rsquo;utilise une long fil de 10 mètres accordée sur la bande des 20 mètres. Plus précisément, c&amp;rsquo;est une antenne End-Fed Half-Wave (EFHW), que l&amp;rsquo;on traduirait probablement comme : antenne demie-onde alimentée par terminaison.</description>
</item>
<item>
<title>Zig Threading Tutorial</title>
<link>https://noelmrtn.fr/posts/zig_threading/</link>
<link>http://localhost:1313/posts/zig_threading/</link>
<pubDate>Wed, 16 Aug 2023 00:00:00 +0000</pubDate>
<guid>https://noelmrtn.fr/posts/zig_threading/</guid>
<guid>http://localhost:1313/posts/zig_threading/</guid>
<description>Prequel With the release of Zig 0.11.0, the language introduced channels like in Go. However, in the same release, they announced that the support of async functions is postponed (related Github issue); they expect their support for the release 0.13.0.&#xA;Initially, I wanted to test channels, but:&#xA;0.11.0 gets Channel, but unusable because it requires await functions 0.10.0 gets async/await support with the option -fstage1, but the Channel is not part of the language Finally, I switched to the solution of thread pools.</description>
</item>
<item>
<title>Prime Numbers Algorithm, in Zig and C</title>
<link>https://noelmrtn.fr/posts/zig_and_c/</link>
<link>http://localhost:1313/posts/zig_and_c/</link>
<pubDate>Sat, 22 Jul 2023 00:00:00 +0000</pubDate>
<guid>https://noelmrtn.fr/posts/zig_and_c/</guid>
<guid>http://localhost:1313/posts/zig_and_c/</guid>
<description>A colleague of mine told me to try a new programming language named Zig. It is designed closely to C/C++ and is also inspired by Rust. I tried to learn Rust those last years as a replacement for C++. However, the syntax is too complex for me, and I&amp;rsquo;ve struggled too much with the compiler&amp;hellip;&#xA;I tried Zig a few days ago with Zig Learn, which is a detailed tutorial to understand the basics.</description>
</item>
<item>
<title>My Journey Building a Magnetic Loop Antenna</title>
<link>https://noelmrtn.fr/posts/loop_antenna/</link>
<link>http://localhost:1313/posts/loop_antenna/</link>
<pubDate>Sun, 18 Dec 2022 00:00:00 +0000</pubDate>
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<description>Currently, I am living in a Parisian flat, and I love doing HF. But you probably know that the antenna length is proportional to wavelength, and dozens of meters cannot be found in a Parisian flat, believe me. So, I found mag-loop antennas a good compromise to operate from the inside of my flat. I&amp;rsquo;ve looked for numerous antenna models, but for all of them, the price is always high, at least 300€.</description>
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<description>Hello! I am Noël, a Software Engineer (mainly a manager now) in Paris. My centers of interest are low and retro-technology (Arduino, Minitel, esp32), science (former physicist), and amateur radio (F4JJD).&#xA;I began college in Lyon, where I studied physics and chemistry. Then, I focused only on fundamental physics, especially theoretical research. In 2013, I joined the CNRS (French Organization for Research) as a PhD student and pursued into the neutron-star physics field.</description>
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<title>Amateur Radio Booklet</title>
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<pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate>
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<description>The Amateur Radio Booklet consists of a summary of all the needed data when one operates. The booklet is global by design. Thus, one can find resources for all IARU regions.&#xA;Also, the booklet is fully open-sourced under the CC BY-SA 4.0 license license.&#xA;GitHub Repository Current PDF Table of Contents Band Plans Classification of Emissions Q Codes Morse Code Radio Abbreviations Digital Modes International Beacon Project Radio Waves Electricity ITU Prefixes, Regions, and Alphabet QTH Locator Units Mathematics To do Release of the 2023 Edition Preparing the first A5-printed copies </description>
<guid>http://localhost:1313/hambooklet/</guid>
<description>The Amateur Radio Booklet consists of a summary of all the needed data when one operates. The booklet is global by design. Thus, one can find resources for all IARU regions.&#xA;Also, the booklet is fully open-sourced under the CC BY-SA 4.0 license license.&#xA;GitHub 2024.1 Edition Table of Contents Band Plans Classification of Emissions Q Codes Morse Code Radio Abbreviations Digital Modes FT8, FT4 PSK, MFSK, Olivia RTTY WSPR Amateur Satellite ISS QO-100 International Beacon Project Beacon List Frequencies Radio Waves Propagation Solar Weather Antennas Standing Wave Ratio Electricity Kirchhoff&amp;rsquo;s Law Operation Amplifiers Filters &amp;amp; RLC ITU Prefixes Allocation ITU Regions ITU Alphabet QTH Locator Units International System Conversions Decibels Mathematics </description>
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