# PhosphorFAX — HF Weather Fax Decoder

> HF Weather Fax Decoder (iPhone/iPad app by Stuart Woolley.)

- Source: https://appshunter.io/ios/app/phosphorfax/id6820037947 (this page in markdown: same URL + `.md`)
- Developer: [Stuart Woolley](https://appshunter.io/developer/315697638)
- Category: Weather, Utilities
- Price: $0.99
- Age rating: 4+
- Requires: iOS 27.0 · 3 MB
- Languages: American English
- Released: 2026-10-17
- Data updated: 2026-10-19

## What is PhosphorFAX?

PhosphorFAX receives radiofax, the HF weather fax that coast stations broadcast around the clock, and paints each chart line by line on a phosphor CRT display. Hold your iPhone near a shortwave receiver tuned to a weather fax station and watch surface analyses, wind and wave forecasts and ice charts arrive the way they do on a ship's recorder.

It sends as well. Turn a photo, a received chart or the built-in test card into radiofax audio through the speaker, or export it as a WAV.

No internet connection. No external hardware. No account. Just your iPhone and a radio.

HOW TO RECEIVE
Tune your receiver 1.9 kHz below the station's listed frequency in USB, so the signal sits around 1900 Hz. Then on the DECODE screen:

ARM: wait for a start tone, then receive automatically
START: receive now, without waiting for a start tone
STOP: end the chart and save it
CLEAR: discard the chart in progress
Drag to look around the chart, and LATEST takes you back to the newest line
Pinch to zoom, double-tap to fit

The same guide is on the DECODE screen until a chart appears.

HOW LONG IT TAKES
Radiofax is slow, and that is part of its charm.
• The start tone lasts 5 seconds and is recognised within a second or two.
• Phasing follows, up to 30 seconds, while PhosphorFAX locks onto the start of each line. If no phasing is heard, receiving begins anyway after 40 seconds.
• A chart paints from the top at two lines a second at 120 LPM. A full chart takes about 10 minutes, 20 at 60 LPM and 5 at 240 LPM. In the first minute you will see only a thin strip, so give it time.
• On the stop tone the chart is saved to the log and the receiver re-arms for the next one.
• Sending takes as long as receiving: about 10 minutes for a chart at 120 LPM, longer for a tall photo. PhosphorFAX shows the duration before anything plays.

FEATURES
• Real-time radiofax receive at IOC 576 and 288, 60 to 240 lines per minute
• Automatic start and stop, re-arming after every chart
• Phasing lock and automatic slant correction for straight charts
• Automatic centre tracking
• Charts can be re-slanted and shifted after the broadcast has gone
• Live spectrum, waterfall, line scope and signal health panel
• Station list for 22 coast and met stations worldwide, with USB dial frequencies
• Chart log with zoom, levels, rotation, invert, share and save to Photos
• Send a photo, a chart or a test card, or export it as a WAV
• Paper, phosphor or negative chart rendering
• Green and amber phosphor CRT themes
• No accounts, no tracking, no network access

SENDING
PhosphorFAX produces audio and never keys a transmitter. Putting that audio on the air needs an appropriate transmitting licence. Sending into a second phone, or exporting a WAV, needs none.

Colour fax is not supported.

## Is PhosphorFAX safe?

Not enough ratings yet to assess PhosphorFAX.

## Is PhosphorFAX legit?

PhosphorFAX appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for PhosphorFAX is 75 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0 — 2026-10-17

No release notes.

## More apps by Stuart Woolley

- [Wiccan Wheel of the Year](https://appshunter.io/ios/app/wiccan-wheel-of-the-year/id322315841)
- [An Irish Calendar (Féilire)](https://appshunter.io/ios/app/an-irish-calendar-feilire/id323710322)
- [BioFacts!](https://appshunter.io/ios/app/biofacts/id324812281)
- [ChemFacts!](https://appshunter.io/ios/app/chemfacts/id325297696)
- [Wiccan Moon](https://appshunter.io/ios/app/wiccan-moon/id325693580)
- [Meteor Wheel](https://appshunter.io/ios/app/meteor-wheel/id338887663)

All apps by Stuart Woolley: https://appshunter.io/developer/315697638

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-19.*