Comparison

SUNSCAN vs PhosphorRTTY

Price, ratings, monetisation and update history for both apps, side by side โ€” with what reviewers say about each.

Head to head
About

SUNSCAN

Features
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The Sunscan is a revolutionary spectroheliograph designed to allow you to capture images of the Sun in minutes, directly from your smartphone. This complete and autonomous device is the result of several months of work by our team of enthusiasts. With the Sunscan, you will be able to explore the wonders of the Sun like never before. Thanks to our dedicated application, you will be able to control the Sunscan directly from your smartphone or tablet, making the experience even more intuitive and accessible. You will be able to make observations very simply and obtain images of our star automatically without any special knowledge, showing prominences, flares or even sunspots.

About

PhosphorRTTY

Decode Radio Teletype (RTTY) signals in real time using your iPhone's microphone. Listen to shortwave radio transmissions and see the text appear on an authentic phosphor CRT display. No internet or external hardware needed.

Highlights
  • Real-time RTTY signal decoding
  • Authentic phosphor CRT display
  • Automatic signal detection (AFC, baud, shift)
  • Manual tuning options
  • Live signal analysis (FFT, waterfall)
  • Session logging and sharing
  • Customizable display themes
Features
Read full description

PhosphorRTTY decodes Radio Teletype (RTTY) signals in real time using your iPhone or iPad microphone. Hold it near a shortwave radio tuned to an RTTY signal and watch the text appear on screen, character by character, on an authentic phosphor CRT display. No internet connection required. No external hardware. No account. Just your iPhone or iPad and a radio. WHAT IT DECODES RTTY is the oldest digital mode in amateur radio: two audio tones representing mark and space, encoding text via the 5-bit ITA2 (Baudot) alphabet or 7-bit ASCII. PhosphorRTTY handles the standard configurations: Baud rates: 45.45, 50, 75, 100 Bd (auto-detected or manual) Shifts: 170, 450, 850 Hz (auto-detected or manual) ITA2 (Baudot) and ASCII modes USB signals, and LSB signals with mark and space inverted AUTOMATIC SIGNAL DETECTION The app automatically finds and locks onto RTTY signals: AFC (Automatic Frequency Control) acquires and tracks drifting signals Auto-baud detection identifies the transmission speed Auto-shift detection determines the frequency separation Squelch suppresses noise when no signal is present Or disable any of these and tune manually for full control. FOUR TABS DECODE: the main teleprinter display. Decoded text appears character by character as it is received. The status panel shows baud rate, shift, mark and space frequencies, signal quality and lock state. Clear, pause and resume, start and stop. SIGNAL: live signal analysis. FFT spectrum display (0 to 4 kHz) with mark and space cursors, scrolling waterfall, mark and space tone indicators, bit period histogram with baud rate markers, and a paper punch tape visualisation of the decoded data stream. LOG: session history. Every decode session is saved with timestamp, duration, character count and the full decoded text. Copy, share or delete individual sessions, or export them all at once. CONFIG: all parameters. Audio input gain, decode mode (auto or manual for baud, frequency and shift), ASCII mode, mark and space inversion, display theme, font size and RYRY sequence display options. IPHONE AND IPAD On iPad PhosphorRTTY runs natively in every orientation, with larger type and the teleprinter, spectrum, waterfall and punch tape opened out across the full width of the screen. THE DISPLAY Two authentic phosphor CRT themes: Amber (classic teleprinter terminal) Green (military and commercial terminal) Both feature horizontal scanlines, edge vignette and phosphor glow effects. Monospaced font throughout. RYRY test sequences can be dimmed or hidden to keep the display clean. DSP ENGINE The signal processing is done entirely on-device using a per-sample I/Q quadrature demodulation pipeline: Biquad low-pass filtered I/Q channels for each tone Direct mark and space magnitude comparison for bit decisions Digital Phase-Locked Loop (DPLL) with per-transition phase correction for timing recovery 512-point FFT for frequency analysis and AFC Asymmetric envelope detection for robust tone tracking through fading Tested against real over-the-air recordings from the 20m amateur band. Under 1% error rate on clean signals, 4 to 5% on moderate HF conditions with fixed tuning. WHERE TO FIND RTTY Amateur radio: 14.080 to 14.099 MHz (20m band), 7.080 to 7.100 MHz (40m band), 21.080 to 21.100 MHz (15m band). RTTY contests run throughout the year, and during a contest these frequencies are packed with signals. Maritime and commercial RTTY transmissions can be found across the HF spectrum. A shortwave receiver or SDR with audio output is all you need. REQUIREMENTS iPhone or iPad with a microphone iOS or iPadOS 26.2 or later A radio receiver tuned to an RTTY signal (shortwave radio, SDR, or WebSDR audio played through a speaker) No in-app purchases. No subscriptions. No tracking. No network access.

Screenshots

SUNSCAN3 screens
PhosphorRTTY4 screens

Verdict

The call

The clearest difference is price: SUNSCAN at Free against PhosphorRTTY's $0.99. SUNSCAN also leads on update cadence (weekly vs every 4 months) and iOS requirement (15.1 vs 26.2). On ads, in-app purchases and device support there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

SUNSCAN is free to download; PhosphorRTTY costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

SUNSCAN ships an update weekly, PhosphorRTTY every 4 months. The most recent releases landed on October 25, 2026 and October 31, 2026 respectively.

Scorecard3 real differences ยท 5 level
SUNSCAN versus PhosphorRTTY: the parameters behind the verdict, then further details
ParameterSUNSCANPhosphorRTTY
PriceFree โ€” better$0.99
Positive reviewsโ€”100.0% of reviews
Update frequencyWeekly โ€” betterEvery 4 months
AdsNoNo
In-app purchasesNoNo
Monetizationโ€”Paid
DevicesiPhone, iPad, iPod โ€” betteriPhone, iPad
Requires iOS15.1 โ€” better26.2
Further details โ€” not scored
Size48 MB4 MB
Age rating9+4+
DeveloperSTAROSStuart Woolley

In-app purchases

None

SUNSCAN

No in-app purchases

None

PhosphorRTTY

No in-app purchases

Questions

Is SUNSCAN free?
SUNSCAN is free to download, with no in-app purchases.
Is PhosphorRTTY free?
PhosphorRTTY costs $0.99, with no in-app purchases.
Do SUNSCAN or PhosphorRTTY have ads?
Neither SUNSCAN nor PhosphorRTTY shows ads.
Which is updated more often, SUNSCAN or PhosphorRTTY?
SUNSCAN ships an update weekly, and PhosphorRTTY every 4 months. Most recently, SUNSCAN was updated on October 25, 2026 and PhosphorRTTY on October 31, 2026.

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