# PhosphorRTTY vs Spectrum SDR (RTL

The clearest difference is price: Spectrum SDR (RTL at Free against PhosphorRTTY's $0.99. Spectrum SDR (RTL also leads on update cadence (every 11 days vs every 7 months) and device support (3 vs 1). PhosphorRTTY's advantage is in-app purchases (none vs 1). On review sentiment, ads and iOS requirement there is nothing between them.

Spectrum SDR (RTL is free to download; PhosphorRTTY costs $0.99 up front. Spectrum SDR (RTL sells 1 one-off in-app purchase. PhosphorRTTY asks for nothing beyond the download.

PhosphorRTTY ships an update every 7 months, Spectrum SDR (RTL every 11 days. The most recent releases landed on October 14, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | PhosphorRTTY | Spectrum SDR (RTL |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | — | **[4.5 (2 ratings)](https://appshunter.io/ios/app/spectrum-sdr-rtl-sdr/id6764391865/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 7 months | **Every 11 days** |
| Monetization | Paid | **Free** |
| Size | 3 MB | 7 MB |
| Requires iOS | 26.2 | **26.0** |
| Devices | iPhone | **iPhone, iPad, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Stuart Woolley](https://appshunter.io/developer/315697638) | [James Mainwaring](https://appshunter.io/developer/1895761181) |

## What reviewers say

### PhosphorRTTY

[App page](https://appshunter.io/ios/app/phosphorrtty/id6760180586)

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:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### Spectrum SDR (RTL

[App page](https://appshunter.io/ios/app/spectrum-sdr-rtl-sdr/id6764391865)

Explore radio signals with your RTL-SDR dongle. Listen to AM/FM/SSB/CW, view FFT and waterfall displays, and customize your experience. Requires a remote rtl_tcp instance over WiFi.

**Highlights:** Full frequency range support, AM, FM, SSB, CW reception, FFT and Waterfall displays, Adjustable sample rates, Bias tee and gain controls, Squelch functionality, Customizable display options

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Version | $2.99 | one-time |


## Frequently asked questions

### Is PhosphorRTTY free?

PhosphorRTTY costs $0.99, with no in-app purchases.

### Is Spectrum SDR (RTL free?

Spectrum SDR (RTL is free to download, with in-app purchases available.

### Do PhosphorRTTY or Spectrum SDR (RTL have ads?

Neither PhosphorRTTY nor Spectrum SDR (RTL shows ads.

### Which is updated more often, PhosphorRTTY or Spectrum SDR (RTL?

PhosphorRTTY ships an update every 7 months, and Spectrum SDR (RTL every 11 days. Most recently, PhosphorRTTY was updated on October 14, 2026 and Spectrum SDR (RTL on October 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*