In radio engineering and telecommunications, standing wave ratio (SWR) is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide.

SWR is a measure of what is happening to the forward and reverse voltage waveforms and how they compare in size. Let’s look at what happens when a trans-mitter is connected to 50 Ω coax and a 50 Ω antenna. For now, pretend that the coax cable doesn’t have any losses and the transmitter is producing a 1 W CW signal.

2023年2月8日 · SWR 是 Next.js 背后的团队 vecel 开源的一个 用于数据请求的 React Hooks 库. 官方介绍：“SWR” 这个名字来自于 stale-while-revalidate：一种由 HTTP RFC 5861 推广的 HTTP 缓存失效策略。 这种策略首先从缓存中返回数据（过期的），同时发送 fetch 请求（重新验证），最后得到最新数据。 使用 SWR，组件将会 不断地 、 自动 获得最新数据流。 UI 也会一直保持 快速响应。 SWR 的使用非常简单，下面是一个搭配 axios 进行请求的例子： function App () { …

SWR is a React Hooks library for data fetching. SWR first returns the data from cache (stale), then sends the fetch request (revalidate), and finally comes with the up-to-date data again.

2023年12月7日 · SWR (Standing Wave Ratio) affects the power output of your radio. The following table shows the effect of SWR for a transmitter with 4 watts of transmitted power.

在 無線電工程 和 電信 中， 駐波比 （英語： standing wave ratio， SWR）是 負載 阻抗匹配與 傳輸線 或 波導 特性 阻抗匹配 的量度。 阻抗 失配導致沿傳輸線的 駐波，而駐波比定義為沿線的波腹處的部分 駐波 幅度（最大值）與 節點 處的幅度（最小值）之比。

“SWR” 这个名字来自于 stale-while-revalidate：一种由 HTTP RFC 5861 推广的 HTTP 缓存失效策略。 这种策略首先从缓存中返回数据（过期的），同时发送 fetch 请求（重新验证），最后得到最新数据。

all components in the line including the load measuring SWR is easiest way to tell if the system impedance is acceptable ideally, an antenna is purely resistive and its reactance (X) is zero, …

What is SWR? When there is a mismatch between the output impedance of a transmitter and input impedance of an antenna, some of the signal – in the form of a wave – is reflected back down the transmission line to the transmitter. Standing waves of electrical energy will “appear” in the transmission line. SWR is the ratio:

These wattmeters simultaneously display forward/reflected power and SWR all at a glance! They each have individual meter scales for each power range that increase reading accuracy. A True™ Active peak-reading circuit is included for SSB operation (MFJ-891 only). LED backlighting provides smooth and even illumination for easy night viewing.