📡 Current Band Operating Conditions
With a Solar Flux Index of 143 and 138 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 1); polar paths and high-latitude DX should be unaffected.
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
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
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
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
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
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.
| Band Group | Day | Night |
|---|---|---|
| 80 / 40m | Fair | Good |
| 30 / 20m | Good | Good |
| 17 / 15m | Good | Good |
| 12 / 10m | Fair | Poor |
Continuous reference beacon at Fort Collins, CO. Constant power and antenna make it a clean propagation benchmark.
| Band | Spots (30d) | P90 (mi) | Best DX |
|---|---|---|---|
| 40m | 1,999,961 | 1,599 | VK6XT |
| 30m | 1,789,532 | 1,661 | VK6JI |
| 20m | 1,518,873 | 1,647 | FR5DN |
| 15m | 342,532 | 3,057 | FR5DN |
| 10m | 119,468 | 5,412 | VK6LD |
Propagation Primer — Ionospheric Layers
HF Propagation — Ionospheric Layers
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 30-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.