# ST vs SDR

The clearest difference is price: ST at Free against SDR's $44.99. ST also leads on rating (5.0 vs 4.6) and device support (3 vs 1). SDR's advantage is review sentiment (84% vs 50%) and update cadence (every 2 weeks vs every 27 months). On ads and in-app purchases there is nothing between them.

ST is free to download; SDR costs $44.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ST holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: SDR has 72 ratings behind it against 4, so its average is the more settled of the two. Written reviews complicate that: 50% of ST's written reviews are positive against 84% of SDR's, so the app with the better star average is not the one people write more warmly about.

ST ships an update every 27 months, SDR every 2 weeks. Both last shipped on November 3, 2026.

## The numbers

| Metric | ST | SDR |
| --- | --- | --- |
| Price | **Free** | $44.99 |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/st-4001i/id1492225169/reviews)** | [4.6 (72 ratings)](https://appshunter.io/ios/app/sdr-control-mobile/id1673327509/reviews) |
| Number of ratings | 4 | **72** |
| Positive reviews | 50.0% of reviews | **84.3% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 27 months | **Every 2 weeks** |
| Monetization | **Free** | Paid |
| Size | 12 MB | 55 MB |
| Requires iOS | **12.0** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [ICOM INCORPORATED](https://appshunter.io/developer/1193842631) | [Marcus Roskosch](https://appshunter.io/developer/334053438) |

## What reviewers say

### ST

[App page](https://appshunter.io/ios/app/st-4001i/id1492225169)

This app converts photos and images into a format compatible with D-STAR transceivers for the Share Picture function. Users can crop images, add text like call signs, and transfer them wirelessly or via Bluetooth to supported transceivers.

**Highlights:** Image conversion for D-STAR Share Picture, Image cropping, Add text (call signs), Wireless transfer to transceiver, Bluetooth transfer to transceiver, Save cropped image as file

**Features:** macOS Compatibility

**In-app purchases:** none


### SDR

[App page](https://appshunter.io/ios/app/sdr-control-mobile/id1673327509)

Control your Icom radio remotely from your iPhone. View spectrum scope, waterfall, and access all radio controls over Wi-Fi or the internet. Supports various Icom models and includes features for ham radio operators.

**Highlights:** Spectrum scope and waterfall display, Full radio control, Remote operation over Wi-Fi/internet, FT8-Improved and JS8 modes, CW decoder and keyer, Speech transcription and translation, Logbook with ADIF import/export

**Features:** iPhone Duo support

**In-app purchases:** none

**What reviewers like**

- 🚀 Works perfectly with ICOM radios
- 👍 Intuitive and easy to use
- 🌟 Feature-rich and comprehensive
- 💯 Stable and reliable performance
- 📱 Great for remote operation

**What reviewers complain about**

- 🐛 FT8 decoding issues (lower signal levels)
- 🐛 Dialogs do not scale with larger text setting
- 🐛 UI elements can be cramped on iPhone
- 🐛 Some buttons are small and hard to press
- 🐛 Frequency display overlaps buttons

**Reported bugs**

- Dialogs do not scale with larger text setting
- Frequency display overlaps buttons
- FT8 decoding issues (lower signal levels than WSJTX)
- App crashes and leaves radio in transmit
- Logbook export not functional after update

**Requested features**

- Develop for IC-7800
- CarPlay support
- Apple Watch add-on
- Windows version
- JS8call support


## Frequently asked questions

### Is ST free?

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

### Is SDR free?

SDR costs $44.99, with no in-app purchases.

### Which has better reviews, ST or SDR?

ST is rated higher. ST averages 5.0 out of 5 from 4 ratings, while SDR averages 4.6 from 72 ratings.

### Do ST or SDR have ads?

Neither ST nor SDR shows ads.

### Which is updated more often, ST or SDR?

ST ships an update every 27 months, and SDR every 2 weeks. Most recently, ST was updated on November 3, 2026 and SDR on November 3, 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.*