FAQ & Glossary — everything you need to read this dashboard
This console tells you which radio bands are working right now, how far they will reach, and why — all from measured real data, not guesswork. Here's a plain-English primer.
HF radio signals (3–30 MHz) bounce off a charged layer of the upper atmosphere called the ionosphere. When the ionosphere is well-charged, signals bounce a long way. When it's disrupted by solar storms, they don't. This console measures the ionosphere every 5 minutes and tells you what it means for your radio right now.
Everything on this dashboard flows from two key readings shown in large figures on the left side of the console:
This is a direct measurement of how strongly the ionosphere is charged right now, taken by a ground-based radar in Belgium. Higher = better. Think of it as a ceiling: any signal below this frequency going straight up will bounce back down. Most amateur HF bands are between 1.8 and 29 MHz, so foF2 tells you how many of them are open.
foF2 rises through the morning as the sun charges the ionosphere, peaks in the early afternoon, then falls overnight. You'll see this rise and fall clearly on the chart.
Kp measures how disturbed Earth's magnetic field is right now, caused by solar activity. Lower = better. A quiet Kp of 0–2 means everything is stable. A stormy Kp of 5+ means HF propagation is degraded or broken, especially on paths through northern latitudes.
The fastest route is the Band Briefing (right side of the console) and the band ribbon at the very bottom. These translate the raw numbers into plain-English advice. But if you want to think it through yourself, ask these three questions:
This is the most important question. HF bands work differently at different distances. Check the Bands tab for a full guide, but in brief: 80m and 60m for inter-UK (up to ~500 km); 40m and 30m for Europe (500–1500 km); 20m, 15m and 10m for DX (1500+ km).
Check foF2. If it's above the frequency of your chosen band, NVIS (close-range sky-bounce) will work. If you're trying to skip to Europe, check the MUF 1000 reading on the right. For DX, check MUF 3000. Your target frequency must be below the relevant MUF.
Check Kp. If it's 3 or below, you're fine. If it's 5+, expect degraded conditions regardless of foF2 — the storm is overriding normal ionosphere behaviour.
Near Vertical Incidence Skywave — the trick that makes 80m and 60m so good for inter-UK contacts. Instead of bouncing your signal at a low angle to land far away, NVIS deliberately sends it nearly straight up. It comes straight back down over a 0–500 km area around you, covering the whole UK from a single point. This is why 80m is the workhorse band for regional nets and bunker activations. It requires foF2 to be above the band frequency (3.5 MHz for 80m, 5.35 MHz for 60m).
On bands like 40m (7 MHz), signals bounce off the ionosphere at a shallow angle and land far away — typically 800–1500 km from the UK. The area between you and where the signal lands is the skip zone: neither groundwave nor skywave covers it. This means 40m can be excellent for reaching Germany or France while being completely useless for talking to a station 200 km away in the UK. The console warns you when 40m is in the skip zone for inter-UK distances.
The sun drives ionospheric charging, so the ionosphere behaves very differently by day and night. A lower layer called the D-layer forms only in daylight and acts like a sponge — it absorbs signals on the lower frequencies (160m, 80m) rather than letting them reach the F-layer to bounce. So 80m is weak for DX in daytime but excellent at night once the D-layer collapses. Higher frequencies (20m, 15m, 10m) sail straight through the D-layer to the F-layer above, so they are not affected.
Work through the other tabs: The Console for a layout tour, Readings for what every number means, Bands for a per-band guide, and Glossary for any term you're unsure about.
The Solar Propagation Console is a real-time dashboard for UK and northern-European HF amateur radio operators. It combines live ionospheric, geomagnetic and solar data into a single view that tells you, at a glance, which bands are usable right now, for what distance, and why.
Anyone planning a QSO — whether you're sounding out inter-UK 80m for a regional net, looking for European short-skip on 40m, or chasing DX on 20m/15m/10m. Especially useful for bunker activators and portable operators who need to pick the right band quickly. The Activator Helper tool is designed specifically for UKBOTA operators.
The console is organised around distance. Reading left to right:
foF2 (top) is the raw ionosphere strength measured right now. Kp Index (bottom) is the disturbance level. Below the Kp number, four dials give a visual read of K-Index, A-Index, Solar Flux and Sunspot Number at a glance.
Two charts show how the headline numbers have trended over time. The foF2 chart (top) shows the ionosphere rising and falling with the sun. The Kp chart (bottom) shows geomagnetic storm activity. Use the time-range buttons (3H / 12H / 24H / TODAY / 72H) to zoom in or out.
The X-Ray Flux strip warns of solar flares. The Band Briefing translates numbers into plain-English advice by distance. The quick-action buttons open deeper tools: Today Band Clock, My FT8 Reports, 6m Es monitor, and 2M Tropo monitor. The MUF boxes (bottom) show the Maximum Usable Frequency for three key distances.
A live GOOD / FAIR / POOR verdict for every amateur HF band, updated every 5 minutes.
Data refreshes every 5 minutes in the background. The page auto-reloads every 5 minutes when the tab is visible — hidden tabs are paused, and tabs returning from a long absence reload immediately.
UTC is the universal standard for ionospheric data, space weather, and amateur radio logging. This applies to the toolbar clock, chart X-axes, peak foF2 timestamps, and the briefing "updated" indicator. UTC is one hour behind UK civil time in summer (BST) and matches UK civil time in winter (GMT).
Full detail on each source is in the Data & Timing tab.
The Distance map and Activator Helper in the top toolbar are covered in the Tools tab.
The highest frequency that reflects vertically off the F2 ionospheric layer — directly measured by the Dourbes ionosonde every 15 minutes. This is the single most important propagation number. Any signal below this frequency sent nearly straight up returns to Earth within ~500 km (NVIS). Any frequency above it punches through into space.
Typical daily range: 3–5 MHz at night, rising to 8–14 MHz on a good solar-cycle day. The arrow (↑ ↓ →) shows whether foF2 is rising, falling or stable.
NVIS rule of thumb: foF2 must be at least 0.5 MHz above your band's lower edge — e.g. ≥ 4.0 MHz for 80m, ≥ 5.9 MHz for 60m, ≥ 7.5 MHz for 40m.
Planetary geomagnetic activity, published every 3 hours by NOAA. High Kp compresses and disturbs the ionosphere, degrading HF propagation — especially on polar and high-latitude paths (Scandinavia, Iceland, transatlantic).
The 2×2 dial grid beneath the Kp number shows four complementary indicators that together paint a picture of solar cycle position and today's space weather:
The current Kp value shown visually. Green zone (0–2) = quiet, amber (3–5) = unsettled, red (6–9) = storm. Updates every 3 hours.
The 24-hour average of geomagnetic activity — a slower-moving companion to Kp. Where Kp is a 3-hour snapshot, A-Index reflects the whole day. A-Index above 30 indicates an ongoing storm; above 100 means severe disturbance. A falling A-Index after a high-Kp episode signals recovery.
The Sun's 10.7 cm radio output — a daily proxy for solar activity and F2-layer health. Higher SFI means a more strongly ionised ionosphere and higher MUFs. Follows the 11-year solar cycle closely.
The count of visible dark spots on the Sun's surface. Strongly correlated with SFI. More sunspots = more solar activity = better HF. Smoothed SSN tracks the 11-year solar cycle. We are currently in Solar Cycle 25, which is performing above early predictions.
Solar X-ray output measured by GOES-16, updated every minute. Expressed as a letter class plus a number — each letter is a tenfold increase. Flares on the sunlit side of Earth over-ionise the D-layer, which then absorbs signals rather than letting them reach the F-layer.
Night-time paths are not affected — X-rays don't reach the night-side ionosphere.
Maximum Usable Frequency for a single hop over 500, 1000 or 3000 km. To work a station at that distance your operating frequency must be below the corresponding MUF. Derived from foF2 using standard geometry.
Example: MUF 3000 = 21.2 MHz means 20m (14 MHz) and 17m (18 MHz) are open for DX; 15m (21 MHz) is marginal; 10m (28 MHz) is closed.
The band ribbon at the bottom of the console gives a live verdict for each band. Here's what each band is best suited for and the conditions it needs:
"Top Band." Entirely a night-time band — D-layer absorbs it in daylight. After dark, groundwave covers ~200 km; skywave opens DX to 2000+ km. Requires very large antennas and suffers badly in geomagnetic storms.
The inter-UK workhorse. Groundwave covers ~300 km any time. Daytime NVIS covers the whole UK when foF2 ≥ 4.0 MHz. At night the D-layer collapses — 80m DX to 2000+ km. The reliable fallback when everything else is marginal.
The often-overlooked gem. Excellent NVIS day and night — bridges the gap where 80m gets noisy and 40m is in the skip zone. Needs foF2 ≥ 5.9 MHz for NVIS. Very low atmospheric noise floor compared to 80m.
The European band. Daytime skip lands 500–1500 km away — ideal for Germany, France, Scandinavia. Inside the skip zone for inter-UK at moderate foF2. Night-time: skip zone shrinks, NVIS possible when foF2 ≥ 7.5 MHz, plus DX to 3000+ km. The most versatile HF band.
CW/digital only WARC band. Good for 1000–3000 km at moderate foF2. Less crowded than 40m. Excellent for FT8 into Eastern Europe and the Middle East when 20m is borderline.
The classic DX band. Usually open for global daytime propagation when SFI > 100. The busiest HF band — reliable worldwide contacts across most of the solar cycle. When foF2 peaks, 20m is almost always open somewhere.
WARC band. Similar propagation to 20m but quieter — no contests allowed. Needs slightly higher MUF. Often catches openings that 20m misses due to lower noise and interference.
Solar-cycle sensitive. Opens reliably when SFI > 120. When it's good, it's spectacular — long-haul DX with modest power and simple antennas. Dead at solar minimum; spectacular at maximum.
WARC high band. F2 propagation needs SFI > 150. Also benefits from Sporadic-E in summer (May–August). No contests — very low noise floor. Increasingly useful as Solar Cycle 25 rises.
The solar maximum showcase. Needs SFI > 160 for reliable F2 openings but when it arrives — worldwide contacts with a few watts and a dipole. Completely dead at solar minimum. A barometer of solar activity.
NVIS (Near Vertical Incidence Skywave) — Signal sent steeply upward bounces nearly straight back down over a 50–500 km radius. Requires foF2 above the band frequency. Best achieved with a horizontal antenna 3–10 m above ground. This is how 80m covers the whole UK simultaneously from one point.
Skip propagation — Signal sent at a low angle bounces off the ionosphere and lands 500–3000+ km away in a ring. The area between you and the landing zone is the skip zone — no coverage. 40m skip in daytime lands in Continental Europe, leaving most of the UK unreachable. The skip zone shrinks at night as foF2 rises.
From May to August (and occasionally in December), intense patches of ionisation appear in the E-layer at ~110 km altitude. These Sporadic-E clouds can reflect frequencies up to 200 MHz, producing sudden strong openings on 6m (50 MHz) that last minutes to hours. Unlike F2, Es is unpredictable but very strong when it appears. The 6m Es button in the right rail monitors live UK spots from PSK Reporter.
On 2m (144 MHz), signals normally travel only line-of-sight (~150 km). When temperature inversions form in the lower troposphere, they can duct signals beyond the horizon — sometimes to 500+ km. The 2M Tropo button monitors live 144 MHz spots and shows the Hepburn forecast map.
A line chart of the F2 critical frequency over your selected time range. The rise and fall of foF2 through the day tells you how the ionosphere is responding to the sun — climbing in the morning, peaking in early afternoon, falling overnight. Gaps in the line mean the ionosonde data was temporarily unavailable.
Two horizontal dashed lines appear on the foF2 chart:
Watching foF2 approach the amber line tells you when the next band is about to open. If foF2 is falling toward the green line, the current band is about to close — time to move down.
A bar chart of the planetary Kp index. The Y-axis is always fixed 0–9 so visual comparisons are consistent. Bars are colour-coded by severity:
A Kp chart full of amber and red explains why propagation has been poor — even after the storm ends, the ionosphere needs time to recover.
The YESTERDAY GHOST toggle (beside the range selector) superimposes yesterday's foF2 trace in a muted colour behind today's live data — useful for comparing how conditions are developing compared to the same time yesterday.
Switch between 3H, 12H, 24H, TODAY and 72H using the buttons at top-right. The "Xh collected" pill tells you how much history has accumulated since the plugin was installed. Ranges without enough data appear dimmed.
Accessed via the right-rail button. A 12-hour radial clock view of band openings for the current day — gives a visual overview of when each band has been open and the trend for the rest of the day.
The briefing panel on the right rail translates all the raw numbers into actionable advice, organised by the distances you actually operate at. It is generated algorithmically from live data — not a human forecast.
NVIS territory. The briefing assesses 80m, 60m and 40m for near-vertical propagation at the current foF2 and time of day. It explicitly calls out when 40m is in the skip zone for inter-UK distances and recommends 60m or 80m instead. Thresholds: foF2 ≥ 4.0 MHz for 80m; ≥ 5.9 MHz for 60m; ≥ 7.5 MHz for 40m NVIS.
Single-hop F2 territory, driven by MUF(1000). The briefing identifies which bands are open for contacts with Germany, France, Scandinavia and similar distances. 40m and 30m are the workhorses here.
Single and multi-hop F2 territory, driven by MUF(3000). The briefing tells you which bands are open for long-haul contacts and which direction to point — Mediterranean, West Africa, transatlantic — based on the geometry of a single F2 hop at current foF2.
Solar elevation is computed for London. The briefing adjusts advice accordingly — warning about D-layer absorption on lower bands in daylight, flagging the grey-line DX enhancement at the terminator, and noting when night opens the low bands for DX. Three states: Daytime (sun > 10° elevation), Grey-line (±2°), Night-time (sun < -2°).
If an M or X class solar flare is detected and the UK is on the sunlit side of Earth, a coloured warning bar appears at the top of the right rail. These include a plain-English description of the expected HF impact and what to do. Warnings clear automatically once the X-ray flux drops below threshold.
Throughout the briefing, band references appear as coloured chips. The good / fair / poor logic is consistent between the briefing, the band ribbon, and the Activator Helper.
Every technical term used in the console, in alphabetical order.
All sources are public and authoritative. The server fetches data on your behalf — your browser never contacts these services directly (except the Hepburn tropo map image and PSK Reporter for live 2M Tropo and FT8 spots).
Provides: Planetary Kp index (3-hourly estimates) and GOES satellite X-ray flux (1-minute cadence).
Endpoint: services.swpc.noaa.gov
Notes: Kp is updated every 3 hours; the console shows the most recent published value. X-ray flux reflects the current 1-minute average from GOES-16.
Provides: foF2 and MUF(3000)F2 — direct vertical soundings of the ionosphere.
Endpoint: ionosphere.meteo.be
Notes: Station DB049, located at 50.1°N / 4.6°E (~300 km from London). Geographically close to the UK, making its measurements highly representative of UK propagation conditions. The ionosonde sweeps the full HF spectrum roughly every 15 minutes.
Provides: A-Index, Solar Flux Index (SFI), Sunspot Number (SSN).
Endpoint: hamqsl.com/solarxml.php
Notes: Aggregated from NOAA and SIDC. SFI is published once daily (~20:00 UTC); A-Index updates several times daily; SSN is a daily figure.
Provides: Live digital mode reception spots for the 6m Es monitor (50 MHz, UK stations) and the 2M Tropo monitor (144–148 MHz).
Endpoint: retrieve.pskreporter.info
Notes: PSK Reporter enforces one request per IP per 5 minutes. The 6m Es data is fetched server-side (shared across all visitors). The 2M Tropo data and FT8 Reports are fetched directly from your browser (your IP), so they update on demand.
Data is stored in 10-minute buckets and retained for 72 hours. The 3H, 12H, 24H, TODAY and 72H chart views all draw from this accumulated history. The "Xh collected" pill next to the range selector shows how much history is actually available.
All ionospheric and solar data is fetched server-side — your browser only talks to your own WordPress site. Visitor counting uses a one-way SHA-256 hash of IP + date + site secret; no raw IPs are stored, no cookies are set, no cross-session tracking occurs. If upstream sources are temporarily unreachable, the console shows the last cached values; the footer source tag indicates which feeds are live.
The console includes six interactive tools accessible from the toolbar and right rail. All load on demand — no bandwidth cost if unused.
Opens a Leaflet map with concentric range rings at 300 km, 500 km, 1000 km, and 1500 km centred on your location — useful for visualising the geographic reach of each band.
Your position is requested via the browser Geolocation API (10-second timeout). If permission is denied, the map defaults to the console's home station coordinates. Map tiles and Leaflet load on first use only — subsequent opens are instant.
Answers: "What band should I pack for my activation today?" Choose your UK activation region (or tap "Use my location" to auto-detect) and see a full propagation card showing current conditions from that region.
Ten chips — one per other UK region — showing whether you can reach it right now, the distance, the best band, and a GOOD / FAIR / POOR verdict. Your own region shows as a pulsing chip marked HERE. The algorithm accounts for NVIS thresholds, skip zones, and current Kp.
Four distance bands — Near Europe (500–1000 km), Distant Europe (1000–2000 km), Near DX (2000–5000 km), and Distant DX (5000+ km) — each with a best-band recommendation driven by MUF(1000) and MUF(3000).
A single headline — "Pack 40m + 20m" (or similar) — with a one-line explanation. The algorithm surveys all verdicts and surfaces the two bands covering the most paths. Your selected region is saved to browser local storage and remembered next time.
Each UK region uses a population-weighted centroid (e.g. Midlands = near Birmingham) so distances reflect where chasers actually are. Distances use the Haversine great-circle formula. Verdicts factor in: groundwave/near-NVIS (< 100 km), classic NVIS (100–500 km), awkward skip-zone gap (500–800 km), short F2 skip (800–1500 km). Kp above 5 forces "poor" for high-latitude paths.
A 12-hour radial clock showing how band conditions have developed through the current day. Useful for planning operating times and spotting patterns such as the mid-afternoon foF2 peak.
Enter your callsign to pull your recent reception reports from PSK Reporter, sorted by band. Shows which stations received you, at what SNR, and how recently — useful for assessing actual propagation on each band from your QTH. Fetched directly from PSK Reporter using your callsign; no account needed.
Live 50 MHz Sporadic-E spots from UK stations (G, M, 2E callsigns) in the last 20 minutes, sourced from PSK Reporter. Updates every 5 minutes (server-side, shared cache). The OPEN / WATCH status also shows on the toolbar button — visible at a glance without opening the modal.
Live 144–148 MHz tropospheric scatter spots from PSK Reporter, fetched directly from your browser and updated on demand. Columns show each transmitting station; rows show receivers, distance, SNR and age. Also displays the Hepburn troposcatter forecast map for North-west Europe — updated approximately hourly. Click the map to open the full dxinfocentre.com forecast.
Visible only to administrators. Counts are unique visitors — the same person reloading all day counts once per day.
Each visit's IP address is combined with the current UTC date and a rotating site secret (the WordPress auth key), then hashed with SHA-256. Only the hash is stored — the raw IP is never written. Because the date is part of the salt, the same visitor produces a different hash each day, allowing daily unique counts without identifying or tracking anyone across sessions.
Known bots and crawlers are filtered by User-Agent before counting. Admin users are excluded. Hashes older than 30 days are pruned automatically.
Visible only to administrators. Counts are unique visitors — the same person reloading the page all day counts once per day.
Each visit's IP is combined with the current date and a rotating site secret, then hashed with SHA-256. Only the hash is stored — the raw IP is discarded. Because the date is part of the salt, the same visitor produces a different hash each day, so we can count daily uniques without being able to identify or track anyone. Hashes older than 30 days are pruned automatically.
Bots and crawlers are filtered by user-agent before counting. Admin users (you) are excluded.
Pick your activation region — see exactly where you'll be heard and what to pack.
Choose a region above to see how the ionosphere favours your activation right now.
Inter-UK bunker NVIS digest · updated every 5 minutes with live ionospheric data
Looking back over the past 24 hours from 17:27 UTC yesterday: the period opened with foF2 at 6.7 MHz — below the 40m NVIS threshold, with 60m or 80m the more practical inter-UK band at that point. Conditions were actually at their best right at the start of the window, peaking at 21:27 UTC yesterday overnight at 7.2 MHz before easing through the rest of the period. The low point of 4.2 MHz came at 05:56 UTC this morning — at that level 40m was in the skip zone for most NVIS paths, with 80m the sensible choice for inter-UK work during that spell.
40m NVIS last closed at 22:17 UTC yesterday overnight at 22:17 UTC, when foF2 dropped below 7.0 MHz. It had previously risen above threshold at 21:17 UTC yesterday overnight at 21:17 UTC. At the current foF2 of 5.7 MHz, 40m NVIS remains closed — 60m or 80m are the better inter-UK options until foF2 recovers.
To illustrate how these conditions played out on actual bunker paths — these are selected examples only and do not represent every possible inter-UK route — the shorter Southern England to the Midlands path (154 km) was well-served by 40m NVIS at the period's peak, with groundwave covering the closer portions of that route throughout. The the Midlands to Central Scotland path (around 405 km) is classic NVIS territory — this was comfortably achievable on 40m when foF2 was at its best. The Southern England to Northern Ireland path (516 km) sits beyond the worst of the skip zone — NVIS was marginal at that range during the period, but a low-angle F2 hop may have made the path viable even when foF2 was below the pure NVIS threshold. Worth trying rather than ruling out.
At 5.7 MHz, foF2 is currently below the 40m NVIS threshold. 40m is in the skip zone for typical inter-UK NVIS distances — paths in the 150–500 km range will find 60m or 80m more productive. Paths under 100 km are still workable on 40m groundwave, and those beyond 500 km may still be possible via a low-angle F2 hop, though with less certainty. FoF2 is running flat over the past two hours.
For anyone considering getting on the air: 40m NVIS is not the right tool for most inter-UK paths right now — it is in the skip zone for the 150–500 km range. Lead with 60m, or 80m as a further fallback. Shorter paths under 100 km remain workable on 40m groundwave. If you are working a longer path beyond 500 km, a 40m contact may still happen via a marginal F2 hop — worth a call, but do not rely on it. Watch foF2 — if it climbs back through 7.0 MHz, 40m NVIS will come back into play.
NVIS viability by band — today UTC — 10-minute buckets — fixed ring positions
Live PSK Reporter spots · 144–148 MHz · UK at least one end · last 20 min · columns by transmitting station
50 MHz · UK stations (G / M / 2E) · PSK Reporter live data · 20-minute window · updates every 5 min
| UK station | Heard by | Country | Distance | Dir | Mode | Age |
|---|