RF Engineer's Calc vs VibeSDR
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RF Engineer's Calc
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A simple RF Engineer's Calculator. Convert Watts to dBm, calculate dBm power changes, convert Return Loss to VSWR, etc...
VibeSDR
This app acts as a versatile receiver client for various software-defined radio servers. It offers advanced display, tuning, and audio features, along with on-device decoders and voice control for a comprehensive radio experience.
- Connects to multiple SDR server protocols
- GPU-rendered waterfall and spectrum display
- Native background audio playback
- On-device decoders for RTTY, NAVTEX, WEFAX, SSTV, Morse
- Voice control via Siri
- CarPlay and Apple Watch integration
- Deep linking for station tuning
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VibeSDR is a mobile-first software-defined radio (SDR) receiver — and far more than a single-server client. It speaks multiple SDR server protocols and does its own demodulation of the raw IQ with a clean-room DSP engine. Pair that with a GPU-rendered waterfall, native background audio, on-device decoders and maps, plus voice and in-car control, for a genuinely great SDR experience on any iPhone — whatever receiver is behind it. WHAT YOU CAN CONNECT TO • Remote SDR servers — native support for UberSDR, OpenWebRX / OpenWebRX+, and KiwiSDR, all behind one interface, with a directory chooser in the instance picker. • Networked rtl_tcp — connect to a remote rtl_tcp server and VibeSDR demodulates the raw IQ itself. DISPLAY & WATERFALL • Custom GPU waterfall and spectrum, rendered with a Skia shader for a smooth, high-frame-rate display independent of the server. • Portrait and landscape layouts, ProMotion 120 Hz, haptic tuning feedback. • Classic colour palettes (GQRX, KiwiSDR, CuteSDR, SdrDx, OpenWebRX), VFO glow controls, and a spectrum backdrop image. TUNING & CONTROLS • VFO drum with inertia scrolling and a dual-drum waterfall zoom. • Full mode set — USB, LSB, AM, SAM, FM, NFM, CW — with passband sliders. • Noise reduction, noise blanker, squelch, AGC, volume and mute. AUDIO • Native audio engines running outside any WebView, so playback survives app suspension. • Background audio on both platforms. • Lock-screen, Now Playing, CarPlay and Apple Watch controls with frequency + station metadata and station/bookmark skipping. • AAC recorder with share sheet. VOICE CONTROL • Siri — "Hey Siri, tune VibeSDR" then a frequency, a station name, or a band; it tunes with the right demodulator and step, even in the background over headphones, CarPlay or the lock screen. DECODERS & MAPS • On-device decoders — RTTY, NAVTEX, WEFAX, SSTV, Morse, and speech-to-text. • Server maps — HFDL aircraft, digital and CW activity maps, fully embedded. STATIONS & BOOKMARKS • Instance picker directory across UberSDR, OpenWebRX/OpenWebRX+ and KiwiSDR receivers, with country flags, favourites and an auto-connect default. • Bookmark and band-plan search with live EiBi schedules. • Visual Tuning System (VTS) — nearby-station bar, band-crossing popups and station skipping. • Live chat, and Share a tuned station as a tappable deep link. NEW: DEEP LINKING • Tap a vibesdr:// link to connect straight to a receiver and tune to the shared frequency — no hunting through the picker. VibeSDR is free software under the GNU GPL-3.0, built by Stuart Carr with AI assistance from Claude (Anthropic). VibeSDR is a receiver client and is not affiliated with the SDR servers it connects to.
Screenshots
Verdict
The clearest difference is price: RF Engineer's Calc at Free against VibeSDR's $2.99. VibeSDR's advantage is update cadence (every 2 weeks vs every 10 months) and device support (3 vs 1). On ads, in-app purchases 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
RF Engineer's Calc is free to download; VibeSDR costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
RF Engineer's Calc ships an update every 10 months, VibeSDR every 2 weeks. Both last shipped on October 6, 2026.
| Parameter | RF Engineer's Calc | VibeSDR |
|---|---|---|
| Price | Free — better | $2.99 |
| Rating | — | 5.0 (1 ratings) — better |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | — | 1 — better |
| Update frequency | Every 10 months | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | — | Paid |
| Devices | iPhone | iPhone, iPad, Apple Watch — better |
| Requires iOS | 16.1 — better | 16.4 |
| Further details — not scored | ||
| Size | 43 MB | 52 MB |
| Age rating | 4+ | 4+ |
| Developer | GRAHAM JOHN SMITH | Stuart Carr |
In-app purchases
RF Engineer's Calc
No in-app purchases
VibeSDR
No in-app purchases









