rtl_tcp SDR vs SDR
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.
SDR
Control your Icom transceiver remotely or locally from your iPhone. Operate in all modes, log QSOs, and utilize integrated digital modes like FT8/FT4 and SSTV. No extra hardware is needed for global access.
- Remote transceiver operation
- All mode control
- Auto logging logbook
- Integrated FT8/FT4 tool
- Integrated SSTV receiver
- Integrated CW decoder and keyer
- DX-Cluster integration
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Your Icom radio on your iPhone: at home over Wi-Fi or from anywhere over the internet. Made by a ham, for hams, with personal support included. SDR-Control Mobile shows the spectrum scope and waterfall of your Icom radio with all its controls. No extra hardware or software needed. WORKS WITH ■ IC-705 (Wi-Fi) ■ IC-7610, IC-7760, IC-9700, IC-7300 MK2 and the IC-R8600 receiver (radio on your network by cable) The app connects over the network only. The older IC-7300 (without MK2) has no network connection and can't be used. OPERATE ■ Spectrum scope and waterfall with band plan, DX Cluster and FT8 spots ■ Two VFOs, filters, preamp, attenuator, NB, NR, notch, AGC and more ■ Compact floating panels: tuning, PTT, CW, memories, macros, Command Bar, DTMF, RIT / ∆TX, D-Star ■ Your iPhone as microphone and speaker; the radio keeps playing in the background ■ Ready for iPhone Duo: the iPhone screens when folded, the large radio screen when open MODES ■ FT8-Improved with AutoAnswer and AutoCQ, plus the classic FT8 ■ JS8 keyboard chat ■ CW with decoder, keyer and CW keyboard ■ Speech: incoming voice transcribed and translated, your typed text sent as speech ■ SSTV, HF-Fax, APRS, WSPR and D-Star FT8-Improved, JS8, Speech and WSPR need iOS 26. TOOLS ■ Logbook with ADIF import and export, shared via iCloud with SmartSDR, FT-Control, TS-Control and K4-Control, on iPhone, iPad and Mac ■ DX Cluster, POTA, PSK Reporter, Call Lookup, Band Plan, Network Stats, Memories, Scanning ■ Controllers: MIDI, CTR2, HaliKey, Pryme, Flic ■ 4O3A Genius devices and Ultra Beam antennas MADE BY A HAM Made by Marcus, DL8MRE, who has been developing apps for Apple devices since 2009 and uses this app every day in his own shack, where all supported radios are on the desk. Personal online support and a detailed manual are included. Updates with new modes and features are free: no subscription, no in-app purchases. WHAT YOU NEED ■ One of the radios above, connected to your network ■ An iPhone with iOS 18 or later ■ For use over the internet: access to your home network from outside (see the manual) Manual: https://go-to.me/sdrcontrol-mobile-manual More apps: https://ham-radio-apps.com
Screenshots
Verdict
The clearest difference is price: rtl_tcp SDR at $12.99 against SDR's $44.99. SDR's advantage is review sentiment (84% vs 40%) and rating (4.6 vs 3.9). On ratings volume, ads, in-app purchases and monetization model 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 SDR $44.99 up front. Neither carries in-app purchases, so what you see is what you pay.
SDR holds the better App Store score, 4.6 against 3.9. Both are backed by a comparable volume of ratings — 32 and 67 respectively. Written reviews point the same way: 40% of rtl_tcp SDR's written reviews are positive against 84% of SDR's.
rtl_tcp SDR ships an update every 4 months, SDR every 2 weeks. The most recent releases landed on October 23, 2026 and October 25, 2026 respectively.
| Parameter | rtl_tcp SDR | SDR |
|---|---|---|
| Price | $12.99 — better | $44.99 |
| Rating | 3.9 (32 ratings) | 4.6 (67 ratings) — better |
| Positive reviews | 40.0% of reviews | 84.3% of reviews — better |
| Number of ratings | 32 | 67 — better |
| Update frequency | Every 4 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 16.6 — better | 17.6 |
| Further details — not scored | ||
| Size | 3 MB | 55 MB |
| Age rating | 4+ | 4+ |
| Developer | HotPaw Productions | Marcus Roskosch |
Customer experience
rtl_tcp SDR
SDR
Bugs and requests
rtl_tcp SDR
Not enough reviews yet to summarise bugs or requests.
SDR
Reported bugs
12 issues- 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
Show 7 moreShow fewer
- Function button for horizontal scrolling not fully displayed
- FT8 decode is useless and unreliable
- Messed up radio, requiring reset
- RX audio unusable outside home network (prior to 1.5.1)
- Struggles with audio RX packets on remote cellular networks
- Cannot work over mobile data with certain carriers (EE)
- FT8 alerts sound but don't display
Requested features
14 requests- Develop for IC-7800
- CarPlay support
- Apple Watch add-on
- Windows version
- JS8call support
Show 9 moreShow fewer
- More digital modes
- Display memory bank names
- Initiate memory scan from app
- WSPR implementation
- Tool for WSPR
- More FT8/FT4 features (e.g., setting transmit frequency directly in FT8 view)
- Send image to unit
- KISS TNC support
- Control digital modes (reflectors, etc.)
In-app purchases
rtl_tcp SDR
No in-app purchases
SDR
No in-app purchases









