PhosphorHertz

HF Band Conditions & Greyline

Only for iPhone

$0.99 · Designed for iPhone

iPhone

Real-time HF propagation from NOAA space weather data. Band conditions, MUF, solar indices, greyline globe, and DX path analysis — all in a retro CRT display. PhosphorHz is a real-time HF radio propagation monitor for amateur radio operators. It pulls live space weather data from NOAA's Space Weather Prediction Center and translates it into band-by-band conditions you can act on — right now, from your location. No guesswork. No stale forecasts. Just the numbers, rendered in a retro CRT phosphor display that would look at home in a Cold War listening post. BAND CONDITIONS See at a glance which HF bands are open, marginal, closed, or blacked out. Conditions are calculated from real-time solar flux, geomagnetic activity, and X-ray flux data — not generic regional forecasts. Each band shows your local status plus path-specific conditions to every DX target you configure. MUF CALCULATION The Maximum Usable Frequency for a 3000km reference path from your QTH, derived from Solar Flux Index, solar zenith angle, and depressed by geomagnetic activity. Individual MUFs are calculated for each great-circle path to your DX targets, because the ionosphere doesn't care about averages. SOLAR INDICES All the numbers that matter, updated in real time: Solar Flux Index (SFI) with 30-day trend chart Planetary Kp Index with 24-hour bar chart Estimated Sunspot Number (SSN) GOES X-ray flux class and latest flare detection Solar wind IMF Bz component NOAA R/S/G scales (Radio Blackout, Solar Radiation, Geomagnetic Storm) Running A-index and solar wind Bt Each index includes a plain-language assessment: is the F2 layer well ionised? Is the geomagnetic field quiet or disturbed? Is the solar wind coupling or shielded? 3D GREYLINE GLOBE A SceneKit globe shows the solar terminator — the boundary between day and night — in real time. The greyline (twilight zone along the terminator) is where lower-band DX propagation is enhanced, and it's rendered as an amber band you can see at a glance. The globe displays coastlines, your QTH position, DX target locations, and great-circle paths coloured by band condition. Drag to rotate. Double-tap to recentre on your station. Hit play to watch the Earth spin. SPACE WEATHER ALERTS NOAA SWPC alerts and warnings filtered for HF relevance. Flare events, geomagnetic storms, radio blackouts — the alerts that actually affect your ability to make contacts, with full detail on tap. DX TARGETS Configure up to five target regions. PhosphorHz calculates path-specific propagation for each one, using great-circle geometry and the MUF at the midpoint of each path. What's open to Japan might be closed to South America — and now you can see both at once. FEATURES Real-time data from NOAA SWPC (public domain, no API key required) Band conditions for 160m through 6m Path-specific propagation to multiple DX targets 3D interactive greyline globe with terminator visualisation Sunrise/sunset times and countdown to next solar event Day/night/greyline status at your QTH Kp index 24-hour bar chart SFI 30-day trend line Full space weather alert log with 30-day history Maidenhead grid locator display Automatic location detection or manual grid entry Green phosphor and amber phosphor CRT themes CRT scanline overlay effect Designed for iPhone, portrait orientation No ads. No tracking. No subscription. Part of the Phosphor suite: PhosphorWX (aviation weather), PhosphorRad (radiation monitoring), PhosphorSol (space weather), and PhosphorOrbit (satellite tracking). 73 de PhosphorHz.

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    Information

    • Seller
      • Stuart Woolley
    • Size
      • 2.9 MB
    • Category
      • Reference
    • Compatibility
      Requires iOS 26.2 or later.
      • iPhone
        Requires iOS 26.2 or later.
      • Mac
        Requires macOS 26.2 or later and a Mac with Apple M1 chip or later.
      • Apple Vision
        Requires visionOS 26.2 or later.
    • Languages
      • English
    • Age Rating
      4+
    • Copyright
      • © 2026 Stuart Woolley
  • Developer Website
  • Privacy Policy

    • Supports

    • Family Sharing

      Up to six family members can use this app with Family Sharing enabled.

    More by Stuart Woolley