File:Antenne gp vhf 4.jpg
Size of this preview: 797 × 600 pixels. Other resolutions: 319 × 240 pixels | 638 × 480 pixels | 1,020 × 768 pixels | 1,280 × 964 pixels | 2,269 × 1,708 pixels.
Original file (2,269 × 1,708 pixels, file size: 561 KB, MIME type: image/jpeg)
 | This is a file from the Wikimedia Commons. Information from its description page there is shown below. Commons is a freely licensed media file repository. You can help. |
Summary
| Description |
Français : L'antenne ground plane ou GPA (Ground Plane Antenna) est un dipôle dans lequel on a remplacé la moitié par un « plan de sol », la moitié conservée étant normale à cette surface. Si le plan de sol est suffisamment grand, le demi-dipôle se comporte exactement comme un dipôle entier (type: dipôle demi-onde λ/2) car sa réflexion dans le plan de sol forme la partie manquante. Dans ce cas, son gain théorique est de 2,14 dBi (où les dBi sont des décibels avec un « i » ajouté pour rappeler qu'il s'agit d'un gain par rapport à une antenne isotrope), la longueur physique est environ égale au quart de la longueur d'onde de la fréquence sur laquelle l'antenne est accordée. Ces brins, disposés en cercle en nombre de 4, ils constituent une surface conductrice de l'électricité, même si cette surface n'est pas parfaite pour être alimenté par un câble coaxial de 50 ohms
English: VHF ground plane antenna. This is a folded quarter-wave whip antenna with four grounded quarter-wave conductors projecting horizontally from the base of the whip to form a "ground plane". Ground plane antennas have an omnidirectional radiation pattern, radiating equal signal strength in all azimuthal directions, with the radiated power maximum in a horizontal direction and decreasing with elevation angle to zero on the antenna axis. The ground conductors serve to lower the radiation pattern so more power is radiated in horizontal directions. The folded vertical element increases the radiation resistance so it is a closer match to standard coaxial cable feedline. |
| Date | |
| Source | Own work |
| Author | F1jmm |
| Camera location |   | View this and other nearby images on: OpenStreetMap |  |
|---|
Licensing
I, the copyright holder of this work, hereby publish it under the following license:
This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
- share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
 |
This is a retouched picture, which means that it has been digitally altered from its original version. Modifications: Gestionnaire d'images lumineuses.
|
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 21:39, 26 March 2017 | | 2,269 × 1,708 (561 KB) | F1jmm | User created page with UploadWizard |
File usage
The following pages on the English Wikipedia use this file (pages on other projects are not listed):
Global file usage
The following other wikis use this file:
- Usage on fa.wikipedia.org
- Usage on it.wikipedia.org
- Usage on zh.wikipedia.org
