HALO antenna what is it. An effective small antenna
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- Автор: Super User
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- Категория: Электроника / cхемотехника
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A halo antenna, also known as a halo, is a specific type of antenna that consists of a center-fed dipole antenna. The dipole, which has a length equal to half the wavelength, is bent into a circular shape with a break directly opposite the feed point. The ends of the dipole are positioned close to each other but do not touch. By modifying the cross-section of the ends, an air capacitor can be formed. The spacing of this capacitor is adjusted to fine-tune the resonant frequency of the antenna.
Typically, the halo antenna is mounted horizontally. In this configuration, it exhibits an approximate omnidirectional radiation pattern, meaning it radiates equally in all directions around the horizontal plane. Moreover, the radiation from this antenna is horizontally polarized, which means that the electric field of the radiated signals is primarily oriented in a horizontal direction.
Overall, the halo antenna's unique design and characteristics make it well-suited for applications where omnidirectional coverage and horizontal polarization are desired.
LoRaWAN: controlling of downlink on Datacake
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- Автор: Super User
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function Encoder(measurements, port) {
// WARNING!!! Please note that this is UTC Time!!!
// Please convert to your local timezone!!!
var startTime = '07:00:00'; // 9am CET
var endTime = '16:00:00'; // 6pm CET
var currentDate = new Date()
startDate = new Date(currentDate.getTime());
startDate.setHours(startTime.split(":")[0]);
startDate.setMinutes(startTime.split(":")[1]);
startDate.setSeconds(startTime.split(":")[2]);
endDate = new Date(currentDate.getTime());
endDate.setHours(endTime.split(":")[0]);
endDate.setMinutes(endTime.split(":")[1]);
endDate.setSeconds(endTime.split(":")[2]);
// Check if is valid
var valid = startDate < currentDate && endDate > currentDate
// if the current time lies within the desired timeframe
if (valid) {
// send the actual downlink, replace with yours
if(measurements.LED_ON.value) return [1];
else return [0];
}
// in case it is not valid, do not return anything here
// in order to abort sending a downlink
}
To realize more:
CoCo Antenna 868M Collection
- Информация о материале
- Автор: Super User
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- Категория: Электроника / cхемотехника
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2. https://keptenkurk.wordpress.com/2018/03/26/a-lora-868mhz-collinear-antenna/
3. https://keptenkurk.files.wordpress.com/2018/03/coaxcollinearlora1.jpg
SharpDevelop-5.2.1 (Alternate of Visual Studio)
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- Автор: Super User
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- Категория: Программирование
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Рейтинг: 5 / 5
Легковесный простой и быстрый как в старые добрые времена
Kt
Enjoy!
Wireguide on VPS true working guide
- Информация о материале
- Автор: Super User
- Родительская категория: Заметки
- Категория: Компьютерная повседневность
- Просмотров: 820
then
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