Comparison

rtl_tcp SDR vs Gridi

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • 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
Features
Currently charting
Read full description

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.

About

Gridi

Features
Read full description

Gridi is a smart energy monitoring app designed for home users. It provides real-time monitoring of solar power generation, battery storage, EV charging, and heat pump operation in residential energy systems. With Gridi, homeowners can stay informed of their energy usage and optimize it for efficiency and sustainability. Key Features: Real-time monitoring of PV, battery, EV charger, and heat pump systems Supports various energy modes: self-consumption, peak shaving, backup, and more Remote access via smartphone with clear, user-friendly data display Multilingual interface designed for global home users Who is it for: Homeowners with solar, battery, EV charging, or heat pump systems.

Screenshots

rtl_tcp SDR3 screens
Gridi3 screens

Verdict

The call

The clearest difference is price: Gridi at Free against rtl_tcp SDR's $12.99. Gridi also leads on update cadence (every 2 weeks vs every 4 months) and iOS requirement (13.0 vs 16.6). rtl_tcp SDR's advantage is chart position (#191 vs unranked). On ads, in-app purchases and device support 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

CostPrice · In-app purchases · Ads · Monetization

Gridi is free to download; rtl_tcp SDR costs $12.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

rtl_tcp SDR ships an update every 4 months, Gridi every 2 weeks. The most recent releases landed on October 16, 2026 and October 8, 2026 respectively.

Scorecard4 real differences · 7 level
rtl_tcp SDR versus Gridi: the parameters behind the verdict, then further details
Parameterrtl_tcp SDRGridi
Price$12.99Free — better
Rating3.9 (32 ratings) — better—
Positive reviews40.0% of reviews—
Number of ratings32 — better—
Update frequencyEvery 4 monthsEvery 2 weeks — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
Best chart rank#191 — better—
DevicesiPhone, iPadiPhone, iPod
Requires iOS16.613.0 — better
Further details — not scored
Size3 MB18 MB
Age rating4+17+
DeveloperHotPaw ProductionsSolareast heat pump co.,Ltd

In-app purchases

None

rtl_tcp SDR

No in-app purchases

None

Gridi

No in-app purchases

Questions

Is rtl_tcp SDR free?
rtl_tcp SDR costs $12.99, with no in-app purchases.
Is Gridi free?
Gridi is free to download, with no in-app purchases.
Do rtl_tcp SDR or Gridi have ads?
Neither rtl_tcp SDR nor Gridi shows ads.
Which is updated more often, rtl_tcp SDR or Gridi?
rtl_tcp SDR ships an update every 4 months, and Gridi every 2 weeks. Most recently, rtl_tcp SDR was updated on October 16, 2026 and Gridi on October 8, 2026.

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