# RST Decoder vs Sky107

The clearest difference is ads: Sky107 at none against RST Decoder's shown. Sky107 also leads on update cadence (every 2 weeks vs every 2 months) and monetization model (free vs ad-supported). RST Decoder's advantage is ratings volume (7 vs 1) and iOS requirement (17.0 vs 26.2). On price, rating, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for RST Decoder against 5.0 for Sky107. That said, the two scores are not equally well evidenced: RST Decoder has 7 ratings behind it against 1, so its average is the more settled of the two.

RST Decoder ships an update every 2 months, Sky107 every 2 weeks. The most recent releases landed on October 23, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | RST Decoder | Sky107 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (7 ratings)](https://appshunter.io/ios/app/rst-decoder/id1519587362/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/sky107/id6759820636/reviews) |
| Number of ratings | **7** | 1 |
| Positive reviews | 66.7% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 2 months | **Every 2 weeks** |
| Monetization | Ad-supported | **Free** |
| Size | 6 MB | 69 MB |
| Requires iOS | **17.0** | 26.2 |
| Devices | iPhone | **iPhone, iPad** |
| Age rating | 17+ | 4+ |
| Developer | [koji kamogawa](https://appshunter.io/developer/1488210713) | [Aliaksandr Kharevich](https://appshunter.io/developer/1674263353) |

## What reviewers say

### RST Decoder

[App page](https://appshunter.io/ios/app/rst-decoder/id1519587362)

This application decodes Morse code from your microphone, acting as a practice tool to verify your keying accuracy. It offers advanced features like BPF and FFT decoders with automatic frequency and gain control, allowing for fine-tuning of reception parameters.

**Highlights:** Microphone Morse code decoding, Morse practice and keying check, BPF and FFT decoder options, Auto Frequency Detector (AFD), Auto Gain Control (AGC), Real-time CW signal display, Input signal recording/playback

**In-app purchases:** none


### Sky107

[App page](https://appshunter.io/ios/app/sky107/id6759820636)

This app provides a focused study tool for pilots preparing for the FAA Part 107 Remote Pilot Knowledge Test. It covers the official curriculum with structured lessons, flashcards, and practice exams to ensure comprehensive preparation.

**Highlights:** 13-chapter structured course, Flashcard deck with mastery tracking, 60-question practice exam, FAA reference links, Progress tracking, Offline functionality

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is RST Decoder free?

RST Decoder is free to download, with no in-app purchases.

### Is Sky107 free?

Sky107 is free to download, with no in-app purchases.

### Which has better reviews, RST Decoder or Sky107?

RST Decoder and Sky107 are both rated 5.0 out of 5 on the App Store, from 7 and 1 ratings respectively.

### Do RST Decoder or Sky107 have ads?

RST Decoder shows ads; Sky107 does not.

### Which is updated more often, RST Decoder or Sky107?

RST Decoder ships an update every 2 months, and Sky107 every 2 weeks. Most recently, RST Decoder was updated on October 23, 2026 and Sky107 on October 7, 2026.

---

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