You are about to call CQ — or chase a rare DX station — and you want to know whether the HF bands are actually open. The Band Conditions tool pulls four live solar and geomagnetic indicators from NOAA’s Space Weather Prediction Center and shows, in plain words, what they mean for HF right now. No sign-up, no settings; the numbers load the moment the page opens.

Looking for the other utilities? Browse all tools on the Toolbox hub.

Why the Sun Decides Your HF Evening

HF signals travel around the planet by bouncing off the ionosphere — the electrically charged layer high above the Earth. Solar activity strengthens it; geomagnetic storms disturb it. Four numbers capture that state at a glance: the Kp index (how disturbed Earth’s magnetic field is), the Dst index (how deep a magnetic storm runs), solar X-ray flux (whether a flare just fired), and the sunspot number (the long-term health of the solar cycle). Those four numbers are exactly what this tool shows.

The Only Control: Refresh

The tool has no inputs to fill in — there is nothing to configure. On load, your browser fetches all four NOAA feeds directly and fills the cards by itself.

The single control is the Refresh (刷新) button at the top. Press it to re-pull all four feeds. While a refresh is running the button dims (so you know it is working), and the small line next to it shows the fetch time — *”Updated 10/17/2026, 12:40 PM”* style — so you can tell how fresh the numbers are. There is no automatic refresh: if you leave the page open for an hour, press the button before trusting the numbers again.

Walkthrough: A Typical Reading

Open the tool. After a second or two, all four cards fill in. The timestamp line reads, for example, *”Updated 10/17/2026, 12:40 PM”*.
Suppose the Kp index card shows 3.0 / 9 with a yellow Unsettled pill and the sub-line *”NOAA G-scale: G0”*.
The Dst index card shows −12 nT with a green Quiet pill; the X-ray flux card shows C2.1 with a green Normal pill; the Sunspot number card shows 118 with a green Moderate pill.
Below the cards, the “What this means for HF” box assembles a sentence from those values: *”Kp 3.0: unsettled — higher bands may be noisy. No storm signatures — generally fair HF conditions. Higher sunspot numbers favor the upper HF bands. Rough guide only.”*

That is the entire workflow: load, read the pills and the plain-language hint, decide whether to bother with 20 meters tonight.

How to Read the Result

Kp index card — planetary geomagnetic disturbance, on a 0–9 scale, from NOAA’s one-minute estimated-Kp feed. The colored pill is the quick read: Quiet (green) below 3, Unsettled (yellow) at 3+, Active (yellow) at 4+, and Storm (red) at 5+, with the sub-line showing the matching NOAA G-scale grade — G1 at Kp 5 up to G5 at Kp 9 (G0 when quiet).
Dst index card — ring-current storm strength in nanotesla, from the Kyoto Dst hourly feed. Values near zero are quiet; Weak storm (yellow) at −30 nT, Moderate storm (red) at −50 nT, and Intense storm (red) at −100 nT.
Solar X-ray flux card — the strongest GOES X-ray flux in the last 6 hours, expressed as a flare class: A, B, C, M, or X, with a magnitude (e.g. M2.4, X1.0). Normal (green) means nothing remarkable; M-class flare (yellow) means the dayside HF may have faded briefly; X-class flare (red) means a dayside HF blackout was possible.
Sunspot number card — the monthly-mean sunspot number from SILSO. High (green) at 150+, Moderate (green) at 75+, Low (yellow) below 75. This is the slow-moving background number: high sunspot counts are what open the upper HF bands (15, 12, 10 meters).
“What this means for HF” box — a plain-language verdict built from the four values using the page’s own rules: storms in progress, recent flares, or unsettled conditions get named; if none are present it says *”No storm signatures — generally fair HF conditions.”* It always ends with *”Rough guide only.”*
Grey pill (“unavailable”) — if a card shows *n/a* with a grey pill, that one NOAA feed did not answer. The other cards still load independently; press Refresh and try again later.

When to Use It: HF Planning, DXing, and Shortwave Listening

Before chasing DX. A rare station is spotted, but is the band open or are you calling into a storm? One glance at the Kp and X-ray cards settles whether to call now or wait.
Morning contest check. Before a contest weekend, check whether a geomagnetic storm is in progress — it decides which bands get your attention and which get skipped.
Diagnosing a dead band. Bands silent? The tool tells you whether propagation is genuinely poor or whether you should look at your antenna and local noise instead.
Shortwave listening. Planning an evening of shortwave listening? Unsettled or storm-level Kp explains noisy, fading signals — and tells you which nights are worth the effort.

Limitations

Upstream feeds must be reachable. The tool fetches four NOAA SWPC feeds directly in your browser. If any feed is down or your network blocks it, that card shows “n/a” instead of a value.
Snapshots, not guarantees. The numbers describe solar and geomagnetic conditions right now — they do not promise an opening on any particular band, path, or hour.
Global averages. Kp and Dst are planetary indices. A stormy Kp can still leave your specific path fine, and a quiet Kp does not fix bad local noise.
Rough guide by design. The tool page says it itself: local noise, your antenna, and the greyline matter just as much as the space-weather numbers.

Frequently Asked Questions

Does a green “Quiet” Kp guarantee the bands are open?

No. Kp and Dst are planetary averages, and they describe geomagnetic conditions, not a specific band or path. Quiet numbers mean nothing is actively disturbing the ionosphere — but local noise, your antenna, and the time of day still decide whether you hear anything. Treat the tool as guidance, not a promise.

How fresh is the data? Does the page update by itself?

The data is fetched live in your browser each time the page loads. After that it stays put — there is no automatic refresh. The timestamp line next to the Refresh button tells you when the numbers were last pulled; press Refresh before acting on a reading that has been sitting for a while.

What does the G-scale grade under the Kp value mean?

It is NOAA’s geomagnetic-storm scale, mapped from the Kp value: G1 (minor) starts at Kp 5, up to G5 (extreme) at Kp 9. The tool shows G0 when the field is quiet (Kp below 5).

One card shows “unavailable” while the others load fine. What happened?

That card’s NOAA feed did not respond — the four feeds are fetched independently, so one failure does not stop the rest. Press Refresh; if it still fails, the problem is upstream at NOAA and you can check back later.

Why is Kp high but I’m hearing stations fine?

Kp is a planetary average over three hours, and a path to a particular station can behave very differently from the global picture. Short flares also affect only the dayside. Use the hint box as a starting point, then trust your ears.

Related Tools

Greyline & Sun Times — the tool page itself reminds you the greyline matters as much as the numbers; plan your DX around sunrise and sunset.
Callsign Prefix Lookup — conditions look open and a strange callsign appears — identify which country it belongs to before you call.
Repeater Lookup — HF wiped out by a storm? Switch to VHF/UHF and find a local repeater instead.

Disclaimer

Data comes from public sources (NOAA Space Weather Prediction Center feeds — planetary K-index, Kyoto Dst, GOES X-ray flux, and the SILSO sunspot series — fetched live in your browser) and is provided for reference and education only. Propagation indicators are guidance, not guarantees of band openings. Always verify licensing and operating rules with your national telecommunications authority before transmitting.

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波段传播条件：看懂实时 HF 传播数字

你正准备呼叫 CQ——或追一个稀有 DX 电台——想知道 HF 波段到底通不通。波段传播条件工具从 NOAA 空间天气预报中心拉取四个实时太阳/地磁指标，用大白话告诉你它们对当下 HF 意味着什么。无需注册、无需设置，页面一打开数字就自己加载。

👉 试用波段传播条件工具

想看看其他工具？去工具箱总览页浏览全部工具。

为什么是太阳决定了你的 HF 夜晚

HF 信号靠电离层反射绕地球传播——电离层是地球高空的带电层。太阳活动增强它，地磁暴扰动它。四个数字就能概括当前状态：Kp 指数（地球磁场扰动程度）、Dst 指数（磁暴深度）、太阳 X 射线流量（刚有没有耀斑爆发）、太阳黑子数（太阳活动周期的长期健康度）。这个工具展示的正是这四个数字。

唯一的控件：刷新按钮

工具没有需要填写的输入项——什么都不用设置。页面加载时，你的浏览器会直接从 NOAA 拉取四路数据，自动填满卡片。

唯一的控件是顶部的刷新按钮。按一下就重新拉取全部四路数据。刷新进行中时按钮会变暗（表示正在工作），旁边的小字会显示拉取时间——类似 *”Updated 10/17/2026, 12:40 PM”*——让你知道数字有多新。页面不会自动刷新：如果你开着页面一个小时，行动之前先按一下按钮。

实操演示：一次典型读数

打开工具。一两秒后四个卡片全部填好。时间戳显示类似 *”Updated 10/17/2026, 12:40 PM”*。
假设 Kp 指数卡片显示 3.0 / 9，黄色 Unsettled（小扰动）标签，下方小字 *”NOAA G-scale: G0”*。
Dst 指数卡片显示 −12 nT，绿色 Quiet（平静）；X 射线流量卡片显示 C2.1，绿色 Normal（正常）；太阳黑子数卡片显示 118，绿色 Moderate（中等）。
卡片下方的 “对短波意味着什么”框会根据这些值拼出一句话：*”Kp 3.0：小扰动，高频段可能有噪声。无磁暴迹象——短波条件总体尚可，黑子数高时高频段更佳。仅供粗略参考。”*

整个流程就是这样：打开页面，看标签颜色和大白话提示，决定今晚要不要上 20 米波段。

怎么看懂读数

Kp 指数卡片——行星地磁扰动指数，0–9 级，来自 NOAA 一分钟估算 Kp 数据。彩色标签是快速读法：3 以下 Quiet（平静）绿色、3 起 Unsettled（小扰动）黄色、4 起 Active（活跃）黄色、5 起 Storm（磁暴）红色，下方小字标注对应的 NOAA G 等级——Kp 5 对应 G1，一直到 Kp 9 的 G5（平静时为 G0）。
Dst 指数卡片——环电流磁暴强度，单位纳特斯拉（nT），来自京都 Dst 小时值数据。接近 0 为平静；−30 nT 为弱磁暴黄色，−50 nT 为中等磁暴红色，−100 nT 为强磁暴红色。
太阳 X 射线流量卡片——过去 6 小时内 GOES X 射线最强值，用耀斑等级表示：A、B、C、M、X 加数字（如 M2.4、X1.0）。Normal（正常）绿色表示无异常；M 级耀斑黄色表示向日面短波可能短暂衰落；X 级耀斑红色表示向日面短波可能中断过。
太阳黑子数卡片——SILSO 月均黑子数。150 以上 High（高）绿色、75 以上 Moderate（中等）绿色、75 以下 Low（低）黄色。这是变化缓慢的背景数字：黑子数高，高频段（15、12、10 米）才打得开。
“对短波意味着什么”框——按页面内置规则、根据四个值拼出的大白话结论：有磁暴进行中、有近期耀斑、有扰动都会点名；都没发生就写*”无磁暴迹象——短波条件总体尚可”*。结尾永远是*”仅供粗略参考”*。
灰色 “unavailable” 标签——某张卡片显示 *n/a* 配灰色标签，说明那一路 NOAA 数据没取到。四路是独立拉取的，一路失败不影响其他；按刷新重试即可。

什么时候用得上：HF 规划、DX 通联、短波收听

追 DX 之前。 发现一个稀有电台，但波段是真开了还是正闹磁暴？看一眼 Kp 和 X 射线卡片，就知道现在呼叫还是再等等。
竞赛日的晨检。 竞赛周末开始前，先看有没有地磁暴进行中——它决定你把精力放在哪些波段、跳过哪些波段。
波段”死”了的原因排查。 波段一片寂静？工具告诉你是传播确实不行，还是该去查天线和本地噪声。
短波收听。 计划晚上听短波？Kp 小扰动或磁暴级别就解释了噪声大、信号衰落的原因——也告诉你哪些晚上值得花时间。

局限性

依赖上游数据可达。 工具在你的浏览器里直接拉取四路 NOAA SWPC 数据。如果某路挂了或你的网络连不上，那张卡片就显示 “n/a”。
快照，不是保证。 这些数字描述的是此刻的太阳/地磁状态——不保证某个波段、某条路径、某个小时一定开通。
全球平均值。 Kp 和 Dst 是行星级指数。Kp 偏高时你的具体路径可能照样好使；Kp 平静也救不了本地噪声大。
本来就是粗略参考。 工具页自己写了：本地噪声、你的天线、晨昏线，跟这些太空天气数字一样重要。

常见问题

Kp 显示绿色”平静”，波段就一定开通吗？

不一定。Kp 和 Dst 是行星平均值，描述的是地磁状态，不是某条波段或某条路径。绿色只表示电离层没在受扰动——本地噪声、天线、当天时段同样决定你能不能收到信号。把它当参考，不要当保证。

数据有多新？页面会自动更新吗？

数据在你的浏览器里实时拉取，每次打开页面都会取一次。之后就不再动了——没有自动刷新。刷新按钮旁边的时间戳告诉你数字是何时拉的；放了很久的读数，行动前先按刷新。

Kp 数值下面的 G 等级是什么意思？

是 NOAA 的地磁暴等级，按 Kp 值映射：Kp 5 起为 G1（小），一直到 Kp 9 的 G5（特大）。Kp 低于 5 的平静状态显示 G0。

一张卡片显示 “unavailable”，其他都正常，是怎么回事？

那一路 NOAA 数据没响应——四路是独立拉取的，一路失败不影响其他。按刷新重试；还不行就是 NOAA 上游的问题，过会儿再看。

Kp 明明很高，我怎么还收到台了？

Kp 是三小时的行星平均值，某一条具体路径的表现可能和全球平均差很多；短时耀斑也只影响向日面。提示框是起点，最终还是信自己的耳朵。

免责声明

数据来自公开来源（NOAA 空间天气预报中心数据流——行星 K 指数、京都 Dst、GOES X 射线流量、SILSO 黑子数序列——在你的浏览器中实时获取），仅供参考与学习。传播指标是指导，不是波段开通的保证。发射操作前，请务必向本国电信主管部门核实执照状态与操作规定。

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Band Conditions: How to Read Live HF Propagation Numbers