Current Band Operating Conditions — W2MMD

📡 Current Band Operating Conditions

W2MMD · GCARC Skunkworks · refresh every 3 hours, 6 AM – 9 PM ET

2:15 PM ET Sunday, May 24, 2026

Good — reliable propagation across most bands

Bottom Line — What This Means

With a Solar Flux Index of 137 and 77 sunspots, F-layer ionization is moderate. 40m through 15m are reliable; 10m needs daytime hours and good geomagnetic conditions to open consistently. The geomagnetic field is quiet (Kp 2); polar paths and high-latitude DX should be unaffected.

Space Weather Conditions

137

Solar Flux

77 spots

Solar Flux Index (SFI / F10.7)
Measures ionizing UV from the Sun. Higher SFI = denser F-layer = higher MUF, so 17–10 m open more often and reach farther.

<90 Low · 90–120 Moderate · 120–150 Good · >150 Excellent

Source: NRC Canada Penticton via NOAA SWPC

K-index

geomag (3 hr)

Planetary K-index (Kp)
3-hour quasi-log scale of geomagnetic disturbance (0–9). Storms absorb HF in the polar/auroral zones and suppress MUF worldwide.

0–2 Quiet · 3 Unsettled · 4 Active · 5+ Storm

Source: NOAA SWPC

A-index

24-hr smoothed

A-index (Ap)
24-hour linear average of geomagnetic activity. K-index smoothed over a full day — a fast read on overall daily propagation quality.

<10 Quiet · 10–29 Unsettled · 30–49 Active · >50 Storm

Source: NOAA SWPC

292.0

Solar Wind

km/s

Solar Wind Speed
Speed of the charged-particle stream from the Sun. Elevated speed (>500 km/s) compresses the magnetosphere and raises geomagnetic storm risk, especially with a southward Bz.

Typical 300–500 · 500–700 elevated · >700 storm risk

Source: NOAA SWPC ACE/DSCOVR

B7.6

X-ray

flare class

Solar X-ray Flux / Flare Class
X-rays from solar flares over-ionize the D-layer, causing Sudden Ionospheric Disturbances (SIDs) that absorb HF signals on the sunlit side of Earth.

A/B Quiet · C Minor · M Significant · X Severe blackout risk

Source: NOAA SWPC GOES

S1-S2

Sig Noise

HF noise

Signal/Noise (HF noise level)
Reported background noise level on HF as an S-meter reading. Higher S-numbers mean noisier bands — usually correlates with geomagnetic activity or local QRN.

Source: hamqsl.com (N0NBH)

-2.1 nT

IMF Bz

↓ weak south · watch

Interplanetary Magnetic Field — Bz
The north–south component of the solar wind magnetic field. Sustained southward Bz (negative values) is the primary trigger for geomagnetic storms — solar wind speed alone doesn’t cause storms, Bz pulls the trigger.

>0 Northward, stable · 0 to −5 Watch · −5 to −10 Storm risk · <−10 Storm likely

Source: NOAA SWPC ACE/DSCOVR

3.5 nT

IMF Bt

trend stable

Total IMF Strength (Bt)
Total magnitude of the interplanetary magnetic field. Higher Bt with southward Bz means more energy available to drive geomagnetic disturbance.

Source: NOAA SWPC ACE/DSCOVR

10 reg / 17 sp

Solar Disk

C 50% · M 15% · X 5%

Active Regions on the Visible Disk
Sunspot groups facing Earth. Growing regions with complex magnetic structure produce the strongest flares. M-class flares cause brief HF fadeouts on the sunlit side; X-class can black out HF for hours. Probabilities are NOAA’s 24-hour forecast for the worst region on the disk.

Source: NOAA SWPC

Band Group	Day	Night
80 / 40m	Fair	Good
30 / 20m	Good	Good
17 / 15m	Good	Good
12 / 10m	Fair	Poor

Band ratings by N0NBH (hamqsl.com) derived from NOAA SWPC data.

X-ray flux is B7.6 — the Sun is quiet on the X-ray side, no flare disruption expected. Solar wind is normal at 292 km/s — no extra disturbance from that side. Geomagnetic field is QUIET (A-index 3) — quiet, polar and high-latitude paths should be clean. HF background noise is reported as S1-S2.

Seasonal context: day length is now 14.4 h (73 min sunrise earlier, 74 min sunset later vs. the March equinox). F2-layer day starts ~1 hr before sunrise and ends ~1 hr after sunset, so the upper-band DX window is correspondingly longer (or shorter) than at equinox.

Updated 24 May 2026 1814 GMT · sources: NOAA SWPC, NRC Canada Penticton (SFI), SIDC-SILSO (sunspots), hamqsl.com (N0NBH band ratings) · hover any card for what it means

Band Status — Right Now

40m

7 MHz

OPEN

651 spots / 60 min

Reliable regional band 24/7. Best for 300–500 mi NVIS during the day; long-haul DX after sunset.

30m

10.1 MHz

OPEN

268 spots / 60 min

Round-the-clock workhorse. Daytime DX out to 3,000+ mi; evening regional and continental.

20m

14 MHz

OPEN

331 spots / 60 min

Daytime DX workhorse. Carries trans-continental and trans-oceanic paths whenever the band is open.

15m

21 MHz

OPEN

321 spots / 60 min

Daytime DX band — needs SFI > 100 for consistent openings. Strong long-haul when the F2 cooperates.

10m

28 MHz

OPEN

18 spots / 60 min

High-SFI sunlight-only band. When it opens, paths can be effortless DX; when closed, dead silent.

Status derived from live nowcast — high confidence anywhere = OPEN, medium = FAIR, low/none = LIMITED. WAIT/CLOSED applied for HF bands outside their typical daytime window.

Spot Coverage Globe — Last 60 Minutes

Band:

Each dot = a unique receiver that decoded a GCARC station in the last hour, color-coded by band. The gold star is the FM29 reference point. Click + drag to rotate, scroll to zoom. Hover any dot for receiver/band/distance. Filtering to a single band makes its dots larger so they’re easier to find — particularly useful for thin bands like 10 m where there may be only a handful of decodes.

Which Bands Are Open — by Region

Live data from the GCARC WSPR Network — every spot below was decoded from a club member’s beacon by a remote receiver in the last 60 minutes.

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Typical Patterns — Why Regions Behave This Way

N. America

Reliable regional 24/7 on 40m NVIS. 30m and 20m carry continental and Caribbean DX during daytime. 15m and 10m open coast-to-coast on high-SFI days.

Europe

Trans-Atlantic path opens late afternoon EDT through evening as the terminator approaches Europe. 20m is the workhorse; 15m opens with SFI > 130; 17m and 30m work the gray-line.

S. America

Best on 20m and 15m midday EDT through afternoon. 10m can open via TEP (trans-equatorial propagation) when both ends are near the equator.

Africa

Difficult from FM29 — when it works, late morning through afternoon EDT on 20m and 15m, with gray-line opportunities at sunset.

Asia

Mostly long-path west or polar (20m, 15m). Heavily affected by Kp — quiet geomagnetic conditions are essential.

Oceania

Long-path through Asia or short-path through the Pacific. 20m, 15m, occasionally 10m on high-SFI days; long flight times.

Reference notes — what each region typically does on a normal day, and why. Compare to the live data above to see what’s actually happening right now versus the typical pattern.

What the Ionosphere Is Doing Over FM29 — Last 24 Hours

Measured from local wspr_store, GCARC beacons only. The strongest evidence we have of what propagation is actually doing right here.

Band	24h Spots	Receivers	P90 Reach	Farthest DX	Peak Hour	EU
40m	24,109	361	956	VK6PVL 11,648 mi	02:00	79
30m	14,297	342	3,582	VK6PK 11,633 mi	00:00	125
20m	9,925	469	4,012	VK6QS 11,797 mi	23:00	179
15m	3,062	242	4,071	LU8MIL 5,011 mi	17:00	121
10m	118	25	4,775	5Z4GO 7,681 mi	16:00	1

The ionosphere over FM29 in the last 24 hours supported strong propagation — 51,511 decoded spots across 5 active band(s) of GCARC beacon traffic. 20m was the standout: 469 unique receivers heard club beacons, with P90 reach of 4,012 mi and best DX from VK6QS at 11,797 mi (peak hour 23:00 UTC). The European path was open — 505 unique EU receiver decodes across all bands.

Source: GCARC member stations via wsprnet.org / wspr.live · aggregated from local 7-day store, filtered to the last 24 h.

Current Maximum Usable Frequency

The MUF determines which bands can support F2 propagation to a given region right now. If the MUF to Europe is 18 MHz, then 20 m (14 MHz) is open but 15 m (21 MHz) is not.

→ View the live MUF map at prop.kc2g.com

Near-real-time MUF / FoF2 maps generated every 15 minutes from worldwide ionosonde measurements by KC2G. Map data: GIRO ionosonde network. We link rather than embed; please credit KC2G when sharing his work.

WWV Benchmark — NIST Time Station (WW0WWV)

Continuous reference beacon at Fort Collins, CO. Constant power and antenna make it a clean propagation benchmark.

Band	Spots (30d)	Receivers	P90 (mi)	Best DX
40m	1,964,641	1,018	1,616	VK6KLI
30m	1,931,213	838	1,713	VK6KLI
20m	1,691,350	1,482	1,713	FR5DN
15m	352,775	558	1,840	VK6QS
10m	130,999	349	1,562	VK6LD

Unique receivers per band over the last 30 days. Wider bands = more global ears tuned in.

P90 reach per band — 90% of receivers were closer than this. Higher = farther reliable propagation.

7-Day Solar & Geomagnetic Trend

What is Kp? The planetary K-index is a 0–9 scale of geomagnetic disturbance, sampled every 3 hours. The card values below are the worst Kp of the day. Lower is better for HF: 0–2 quiet · 3–4 unsettled · 5+ storm. Geomagnetic storms absorb HF signals in the polar and auroral zones and can suppress MUF worldwide.

05-17

104

Kp 2

05-18

105

Kp 3

05-19

106

Kp 4

05-20

114

Kp 3

05-21

118

Kp 3

05-22

124

Kp 3

05-23

137

Kp 1

What This Week Did to Propagation

Solar Flux climbed from 104 to 137 over the week (range 104–137). Rising SFI progressively improved upper-HF conditions — 15m and 10m openings should have been more frequent and longer-lasting toward the end of the period. Geomagnetic conditions were mixed: 5 unsettled days (Kp 3–4) and 2 quiet, with no full storms. The worst day was 2026-05-19 at Kp 4 — minor disruption on polar paths but most circuits worked normally. Net effect: a workable week — moderate F2 ionization and quiet geomagnetics favored the middle HF bands (40m–20m), with occasional upper-band openings.

Daily SFI (blue) from NOAA SWPC daily-solar-indices; worst Kp of the day from NOAA SWPC planetary-k-index (3-hour readings, daily max). Green ≤2 quiet, orange 3–4 unsettled, red ≥5 storm.

GCARC Station Performance — Last 7 Days (28 station-band rows · grouped by band)

Call	Spots	Uniq RX	P90 (mi)	Mi/W	Best DX	EU RX	NA RX
40m · 6 stations · sorted by P90 reach
N2LQH	3,586	503	3,938	231	VK5ARG	210	281
K2ZA	13,464	552	3,854	498	VK6PVL	180	352
KD2EIB	121,854	479	2,344	3,747	VK5EI	116	354
KC2GYU	32,459	482	2,155	2,012	VK6PVL	94	372
W2MMD	40,198	381	1,570	1,769	VK5EI	57	313
KE2AQZ	6,901	149	502	1,665	OE3GBB	9	139
30m · 9 stations · sorted by P90 reach
K2ZA	13,898	458	4,000	1,351	VK6PK	170	273
WB2MNF	22,185	285	3,704	7,239	VK5ARG	76	203
KC2GYU	24,220	386	3,468	4,211	VK6PK	91	282
KE2DRJ	14,123	187	914	5,021	VK3ARW	14	170
KE2DST	3,035	101	725	4,008	PD0OHW	4	95
W2MMD	3,093	140	725	4,536	OE3GBB/Q	11	127
K2AA	2	0	0	0	WA2N	0	0
KD2SPJ	521	0	0	0	KB8DOA	0	0
WA2JRZ	7,164	0	0	0	VK3ARW	0	0
20m · 5 stations · sorted by P90 reach
W2LJR	832	107	4,068	10,222	VK4EMM	18	87
K2ZA	10,971	620	4,035	1,580	VK5EI	232	368
N2LQH	3,986	596	4,012	390	VK5EI	247	323
KC2GYU	20,007	601	3,984	5,600	VK6QS	178	407
W2MMD	16,955	407	3,669	4,532	VK5EI	84	308
15m · 4 stations · sorted by P90 reach
N2LQH	867	247	4,079	662	VK5HW	116	119
KC2GYU	4,496	207	3,950	6,547	LU8MIL	59	142
W2MMD	7,006	222	3,941	4,532	LU8MIL	65	150
K2ZA	1,245	189	3,938	1,319	VK5ARG	55	129
10m · 4 stations · sorted by P90 reach
N2LQH	295	80	3,564	150	5Z4GO	2	73
K2ZA	432	87	1,020	734	PP5ZX	0	82
KC2GYU	1,178	80	962	3,258	PP5ZX	0	77
W2MMD	1,956	88	904	2,440	PP5ZX	0	84

Hover any column header for a description. Within each band, stations are sorted by P90 reach descending.

Propagation Primer — Ionospheric Layers

HF Propagation — Ionospheric Layers

W2MMD WSPR · Propagation Primer

F2 layer

F1 layer

E layer

D layer (absorber)

NVIS (40m regional)

F2 skip (20/15m DX)

gray line

D Layer · 60–90 km · Daytime Absorber

Exists only during daylight hours. Absorbs HF signals rather than refracting them — especially at lower frequencies. This is why 40m European and DX paths go quiet during the day. After sunset the D layer rapidly collapses, and lower-band skip paths open dramatically.

E Layer · 90–120 km · Short Skip & Sporadic-E

Present during daylight. Supports relatively short skip distances of roughly 1,000–2,000 km. Sporadic-E (Es) occurs when dense ionized patches form unpredictably, sometimes enabling dramatic openings on 10m and even VHF. Regular E-layer propagation is stable; sporadic-E is not.

F1 Layer · 150–200 km · Daytime Sublayer

Exists only in daylight, merging back into the F2 layer at night. Plays a minor independent role in propagation but contributes some absorption on certain paths. Primarily of interest to propagation scientists rather than operators.

F2 Layer · 200–400 km · The DX Workhorse

The primary layer for all intercontinental HF propagation. The highest and most persistent layer — it survives well into the night. The F2 critical frequency rises and falls with solar ionization. The Solar Flux Index (SFI) shown in the space weather table directly measures the solar output driving F2 ionization — higher SFI unlocks 15m and 10m DX.

NVIS — Near Vertical Incidence Skywave

Signals transmitted at very steep angles refract nearly straight back down, covering a radius of roughly 300–500 km. This fills the “skip zone” dead spot between ground-wave range and long-skip distances, and is the primary mechanism for reliable regional coverage on 40m. The W2MMD beacon’s consistent North American regional reception on 40m is largely NVIS at work.

Skip Distance & the Skip Zone

When a signal refracts off the ionosphere, it lands at a specific distance determined by the frequency and layer height/density. Between the end of ground-wave range and where the refracted signal first lands lies the “skip zone” — a region that hears nothing. Higher frequencies produce longer skip distances. As a band “opens” to a region, the skip distance has shrunk to match that path.

Gray Line

The twilight terminator sweeping across Earth’s surface. Near the gray line, the D layer is absent while the F layer remains ionized, creating a brief window of enhanced propagation. Per-region analyses note peaks at dawn/dusk EDT hours that correspond to gray-line enhancement — the most dramatic openings often happen when both ends of the path are simultaneously near the terminator.

About This Report & the GCARC WSPR Network

This report is generated automatically by the W2MMD Skunkworks system and published every three hours between 6:00 AM and 9:00 PM Eastern time. Propagation data is drawn live from the GCARC WSPR Network database at wspr.wb2mnfai.org and space weather data from NOAA SWPC.

The GCARC WSPR Network

The GCARC WSPR Network is a crowdsourced propagation monitoring project run by the Gloucester County Amateur Radio Club. Its purpose is to operate dozens of simultaneous WSPR transmitters from member home stations across southern New Jersey, creating a dense, distributed propagation sensor network.

Most participating members built their own self-contained WSPR beacon using a TAPR Universal WSPR HAT and a Raspberry Pi 3B. Some set up dedicated wire dipoles for the project, while others feed the beacon into their existing home-station antennas. Each TAPR unit transmits on a single designated HF band, and most beacons run at well below 100 mW. Once deployed, the beacon transmits automatically 24/7, requiring no operator attention. The transmitted signal carries the station’s callsign, Maidenhead grid square, and power level in a narrow 6 Hz 4-FSK signal that can be decoded 28 dB below the noise floor — meaning even a sub-100 mW beacon is routinely heard across continents.

How the Data Flows

WSPR spot data from all participating stations is automatically uploaded in real time to wsprnet.org and wspr.live, the global WSPR public databases, by the thousands of receive stations around the world that decode the signals. The GCARC analysis engine at wspr.wb2mnfai.org continuously scrapes spot records from those databases for every registered club member callsign, archives them in a rolling 7-day store, and produces the propagation statistics shown in this report.

Because the report derives entirely from the WSPR public databases, it is agnostic to how each beacon was built or installed. Any amateur radio station in the southern New Jersey area transmitting WSPR packets — regardless of hardware, antenna, or power level — is welcome to participate.

Want to Participate?

Your spots are already in the global database — all you need to do is register your callsign at the top of wspr.wb2mnfai.org. Your station will automatically appear in the group dashboard and contribute to this report the next time it runs.

GCARC members interested in building a beacon should contact the Skunkworks team at any Saturday clubhouse session or via the club Discord in the #wspr-project channel.

The W2MMD Reference Beacon

W2MMD operates the club’s reference beacon: a QRP Labs Ultimate3S transmitting 100 mW into a 65-foot end-fed wire at 15 feet AGL from the GCARC clubhouse in Mullica Hill NJ (grid FM29jr). The beacon transmits on 40, 30, 20, 15, and 10 meters on a rotating schedule. All non-propagation variables are held constant so that variations in results reflect propagation conditions rather than station differences.

30m: 8:1 antenna SWR reduces effective radiated power to approximately 30 mW. Results on 30m — especially to Africa, South America, and Oceania — are lower bounds.
10m: Si5351A clock generator output rolls off significantly at 28 MHz. Effective power is well below 100 mW. 10m results understate what the band is actually doing.
20m EU reach: The end-fed wire’s radiation pattern favors westbound paths, explaining W2MMD’s lower EU receiver count versus other club stations. EU propagation is healthy — this is an antenna pattern effect, not a propagation limitation.

W2MMD · GCARC Skunkworks · Gloucester County Amateur Radio Club · Mullica Hill NJ FM29jr

Generated 2026-05-24 14:15 EDT · Refreshes every 3 hours, 6 AM – 9 PM ET

Data Sources

WSPR propagation data: GCARC member stations via wsprnet.org & wspr.live, aggregated at wspr.wb2mnfai.org
Space weather telemetry: NOAA Space Weather Prediction Center (SWPC), swpc.noaa.gov
Solar flux (10.7 cm): NRC Canada, Dominion Radio Astrophysical Observatory, Penticton BC
International Sunspot Number: SIDC-SILSO, Royal Observatory of Belgium
Band condition ratings: N0NBH (Paul Herrman), hamqsl.com
MUF / FoF2 maps: KC2G, prop.kc2g.com (linked, not embedded)
WWV reference: NIST, Fort Collins CO (WW0WWV)

Recommended Forecast Resource

For multi-day HF propagation forecasts, Frank Donovan W3LPL publishes an excellent three-day outlook derived from 15+ sources, available Mon/Wed/Fri via The Daily DX (dailydx@TheDailyDX.groups.io). W3LPL’s forecast complements this report — he predicts what will happen; we measure what is happening.

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