KPC • RADIO • THE SUN • PROPAGATION

RADIO CONDITIONS & PROPAGATION

A field dashboard for portable operators: what the Sun and Earth's magnetic field are doing right now, which bands to try first, and what NOAA expects next.

KPC FIELD CALL

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UTC (log time)

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Local

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Sunrise

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Sunset

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Sun times for central Kentucky

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LIVE NOAA / SWPC DATA

What Is Happening Right Now?

All times are UTC (Z). The page refreshes itself every 5 minutes while it is open. A red STALE stamp means NOAA has not updated that product recently — trust it less.

Planetary Kp

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Solar Flux (SFI)

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F10.7 solar radio flux

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Sunspot Number

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Daily SWPC sunspot number

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X-Ray Now

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GOES soft X-ray level

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Geomagnetic Activity

— A-index (running) • — G-scale

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Solar Wind

— km/s • — p/cm³

IMF Bz: — nT • Bt: — nT

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Flares

Radio blackout now: —

Last flare: —

Yesterday: —

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LIVE BAND ESTIMATE

Where Should I Start?

This table is recalculated from the live solar flux, Kp, flare (R) level and whether the Sun is up at your location. It is a KPC rule-of-thumb estimate, not a measurement — always confirm with your ears and the spots.

Band	Now	Later	What to expect
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Plan An Activation

Pick a time in the next few days. Ratings use NOAA's predicted Kp for that 3-hour period, whether the Sun will be up at your location, and today's solar flux (which usually moves slowly).

WHEN (YOUR LOCAL TIME)

Portable tip: don't stop at one band.

If 20m is quiet, check 17m, 15m, 30m or 40m. Space weather changes the odds; it does not replace listening.

Portable tip: work the greyline.

The half hour around your sunrise and sunset (shown at the top) is often the best DX window on 40m, 80m and 160m.

LIVE CONDITIONS

Which Bands Are Active?

Real signal reports around Kentucky, the day/night gray line and the latest solar numbers, so you can pick a band before you leave the truck.

Kp HISTORY & FORECAST

Geomagnetic Activity

The last twelve 3-hour Kp readings, then what NOAA predicts. Green is quiet, gold is active, red is storm level.

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How To Read Kp

Kp 0–2 • QuietThe calm baseline for HF. Band openings still depend on solar flux, time of day and your station.

Kp 3–4 • Unsettled / ActivePaths get more variable, with more fading (QSB). Try more than one band before deciding it is dead.

Kp 5–9 • Storm (G1–G5)Expect weak, fluttery signals, especially on northern and polar paths. Regional 40m contacts often still work.

Next 24 Hours

NOAA's predicted Kp by 3-hour period. Guidance, not a guarantee.

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NOAA SPACE-WEATHER SCALES

R, S & G — Now And Next

Three separate scales for three different effects. Current level is highlighted; NOAA's outlook is below: the chance of a flare blackout (R) or radiation storm (S), and the forecast storm level (G).

R • Radio Blackout

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Solar flares. Wipes out HF on the sunlit side for minutes to hours, lowest bands first.

R1Minor

R2Moderate

R3Strong

R4Severe

R5Extreme

S • Solar Radiation

S—

Energetic particles. Mostly a polar-path problem; rarely affects stateside portable contacts.

S1Minor

S2Moderate

S3Strong

S4Severe

S5Extreme

G • Geomagnetic Storm

G—

Disturbed magnetic field. HF fading for hours to days — but can bring aurora and VHF openings.

G1Minor

G2Moderate

G3Strong

G4Severe

G5Extreme

UTC Day	R1–R2	R3+	S1+	G storm
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CURRENT NOAA ALERTS

Alerts, Watches & Warnings

The newest messages from NOAA SWPC, headline first. Open one for the full text.

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OPERATOR TOOLS

Check Before You Call CQ

Parks On The Air Right Now

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NOAA D-RAP global map showing HF absorption on the sunlit side of Earth — **NOAA D-RAP — where HF is being absorbed right now.** Coloured areas show the highest frequency affected by flare absorption. A clear map means no flare blackout.

POTA Spots ↗Who is on the air in a park right now, and on which band. KC2G MUF Map ↗Near-real-time maximum usable frequency from ionosondes. PSKReporter ↗See where digital signals on each band are actually being heard. Reverse Beacon Net ↗Call CQ on CW and see who hears you and how strong. NOAA D-RAP ↗Full absorption maps, including the polar views. NOAA 3-Day Forecast ↗The forecaster's written reasoning behind the numbers.

HF OPERATOR VIEW

What Do These Numbers Mean For Radio?

No single number tells you whether a band is open. Combine solar activity, geomagnetic activity, time of day, band, antenna, noise level and what you actually hear.

Solar Flux & Sunspots

SFI and sunspot number track how strongly the Sun is ionizing the F layer. Roughly: under 90 favours 40m–20m; 100–140 brings 17m and 15m to life; above 140 is when 12m and 10m shine.

Kp & A-index

Kp is the 3-hour geomagnetic reading; A is the daily-scale version. Low is good. Kp 5+ is a storm: expect fading, flutter and weak northern paths. High flux with low Kp is the sweet spot.

Bz, Solar Wind & X-Rays

Sustained southward (negative) Bz with fast wind (500+ km/s) usually means Kp is about to rise. X-ray class shows flares: C is minor, M5+ can black out the sunlit side, X is major.

KPC FIELD CHECK

What Does This Mean For My Activation?

Green-light setup

Quiet Kp, no R/S/G warning, decent solar flux, and bands producing signals when you listen. Set up, call CQ and see what happens.

Be flexible

Elevated Kp or active solar wind does not mean “stay home.” Try different bands and directions, and lean on 40m and 30m for regional hunters.

Flare blackout (R-scale)

If the bands suddenly go silent in daylight, check the X-ray and D-RAP above. Blackouts usually ease within an hour; higher bands recover first.

Storm conditions (G-scale)

Expect variability for a day or more. CW and FT8 get through when SSB cannot, and regional paths often survive when DX is gone.

PLAIN-ENGLISH GLOSSARY

New To This? Start Here.

SFI (Solar Flux): How much the Sun is energizing the ionosphere. Higher means the upper bands (15m, 12m, 10m) are more likely to open.
Sunspot Number: A count of active regions on the Sun. It rises and falls with SFI over the 11-year solar cycle.
Kp: How disturbed Earth's magnetic field is, 0 to 9, updated every 3 hours. Low is good for HF; 5 or more is a storm.
A-index: The same disturbance as Kp, averaged over a day. Under 10 is quiet; over 30 is stormy.
Bz: The north–south tilt of the magnetic field carried by the solar wind. Negative (southward) for a while means Kp is likely to climb.
X-ray class: Flare strength: A, B, C, M, X, each ten times stronger. Big M and X flares cause daylight radio blackouts.
R / S / G scales: NOAA's 1–5 ratings for radio blackouts, solar radiation storms and geomagnetic storms.
Greyline: The band of twilight around sunrise and sunset. Low-band signals often travel unusually far along it.
NVIS: Near Vertical Incidence Skywave: sending the signal almost straight up so it lands within a few hundred miles. A low wire on 40m or 80m does it well — ideal for in-state contacts.
MUF: Maximum Usable Frequency: the highest frequency the ionosphere will bend back to Earth on a given path right now.
QSB: Fading. Signals that rise and fall, common when Kp is elevated.
Sporadic-E: Short-lived patches of ionization that open 10m and 6m with little warning, mostly late spring and summer.

OFFICIAL SOURCE

NOAA Space Weather Prediction Center

KPC uses public NOAA SWPC products for this dashboard. For detailed charts, forecasts, alerts, watches and warnings, go directly to NOAA.

OPEN NOAA SWPC ↗ALERTS & WARNINGS ↗