rtl_tcp SDR vs RST Scope Pro
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
rtl_tcp SDR
This app acts as a software-defined radio receiver for iOS devices, allowing you to listen to various radio signals and view RF spectrum data. It connects to external SDR peripherals via a network protocol, requiring a separate server setup.
- Listen to AM, FM, SSB, CW signals
- View RF spectrum and waterfall
- Connect to networked RTL-SDR peripherals
- Supports Airspy HF+, SDRPlay, LimeSDR Mini
- Direct connection to Hermes Lite 2
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An RTL-SDR Software Defined Radio receiver app for iOS devices. Listen to AM, FM, SSB and CW radio signals. View an RF spectrum and waterfall. Connect, via the rtl_tcp network protocol, to networked RTL-SDR USB peripherals. This app requires an external rtl_tcp server. iOS devices do not currently support the direct connection of USB peripherals such as an RTL-SDR. Thus, the use of this app requires network access to a server, such as a Raspberry Pi (or Mac), with an RTL-SDR unit plugged into its USB port, and running the rtl_tcp protocol at an TCP/IP network address accessible from your iOS device. This allows a Raspberry Pi (or Mac) to act, essentially, as the USB port adapter for your iOS device. The rtl_tcp SDR app can also connect to hfp_tcp for the Airspy HF+, rsp_tcp for SDRPlay devices, and lmm_tcp for the LimeSDR Mini; see GitHub for server source code. This app can also connect to a Hermes Lite 2 QRP transceiver directly, if it has a known IP address, or through an hl2_tcp server. No support is provided for installing any of the rtl_tcp or other tcp software needed to use this app (with a Raspberry Pi, or otherwise). Please do not download this app unless you are already familiar with Software Defined Radio, have an RTL-SDR or equivalent USB SDR peripheral, and have already installed and tested rtl_tcp on your Raspberry Pi, Mac, or other server. Note that this app requires a very high bandwidth network connection in order to receive streams of real-time RF samples from an RTL-SDR. It is recommended that your rtl_tcp server be on a wired connection rather than on the same WiFi as your iOS device.
RST Scope Pro
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This is an app for amateur radio operators with a narrow band of audio frequency, spectrum scope & waterfall display. You can get a rich display by microphone inputting the speaker output of a radio that does not have a spectrum scope or waterfall function. The FFT allows you to distinguish between the dot and dash of Morse code. [function] 1. Ability to change the speed of the waterfall 2. Ability to adjust the level of audio input 3. Function to switch the display band between wide and narrow 4. Display pause function (pause / cancel by touching the screen) 5. Display scaling for iPhone Display size. 6. Function to switch frequency resolution.(40Hz/20Hz/10Hz) 7. Function to switch between bar graph and line graph 8. Function to switch the cross hatch ON / OFF by longTap 9. Function to switch the USB/LSB by Left/Right Swipe 10.Recording/Playback function of Input Sound 11.File Listing function RST Scope(Free) https://www.youtube.com/watch?v=1s9RvOFp52g
Screenshots
Verdict
The clearest difference is price: RST Scope Pro at $1.99 against rtl_tcp SDR's $12.99. RST Scope Pro also leads on update cadence (every 6 days vs every 4 months). On ads, in-app purchases, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
rtl_tcp SDR costs $12.99 and RST Scope Pro $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.
rtl_tcp SDR ships an update every 4 months, RST Scope Pro every 6 days. The most recent releases landed on October 29, 2026 and October 27, 2026 respectively.
| Parameter | rtl_tcp SDR | RST Scope Pro |
|---|---|---|
| Price | $12.99 | $1.99 — better |
| Rating | 3.9 (32 ratings) — better | — |
| Positive reviews | 40.0% of reviews | — |
| Number of ratings | 32 — better | — |
| Update frequency | Every 4 months | Every 6 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad | iPhone, iPod |
| Requires iOS | 16.6 | 15.6 — better |
| Further details — not scored | ||
| Size | 3 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | HotPaw Productions | koji kamogawa |
In-app purchases
rtl_tcp SDR
No in-app purchases
RST Scope Pro
No in-app purchases








