Comparison

RST Decoder Pro vs arduinoSG90

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

Head to head
About

RST Decoder Pro

This application decodes Morse code from your device's microphone, offering two decoding methods (BPF and FFT) with adjustable parameters. It includes features like automatic frequency detection, gain control, and real-time signal display for accurate Morse code practice and reception.

Highlights
  • Microphone Morse code decoding
  • BPF and FFT decoding methods
  • Auto Frequency Detector (AFD)
  • Auto Gain Control (AGC)
  • Real-time CW signal display
  • Waterfall display (Pro version)
  • Adjustable control parameters
Read full description

This is an App that decodes Morse code input from the microphone. I recommend that you try the basic functions and usage with the free version before purchasing. It is a Morse practice App that you can use to check if you are keying the correct code. Signals with good S/N can be decoded correctly, but signals with bad S/N cannot be decoded correctly. Also, the performance will be degraded for extremely slow or fast signals. Usually about 5 to 10 characters are required for speed synchronization of Morse Code. Adjust the input signal so that the peak value changes from level 6 to level 7. Make fine adjustments to each parameter according to the reception status. [Additional Functions] -In addition to the decoder using BPF, a new decoder using FFT has been added so that it can be switched according to the usage. -AFD (Auto Frequency Detector) function has been added to the decoder using BPF, and BPF can be set automatically by pressing the AFD button. -The decoder using FFT automatically follows the strongest signal in the band by AFD (Auto Frequency Detector) and AGC (Auto Gain Control). You can also hold the AFD / AGC parameters by pressing the Lock button. * There will be a time lag of about 1 to 2 seconds for AFD tracking. * The Pro version also supports waterfall display. [Control parameters] 1.Language select English and Japanese(KANA) 2.Audio Input Level 3.BPF ON/OFF 4.BPF of Center Frequency 5.BPF of Band Width 6.BPF of Shape 7.Notch ON/OFF 8.Notch of Center Frequency 9.CW Speed Control ON/OFF 10.CW Speed Control Low, Mid1, Mid2 or High 11.Delete All Decoded Text 12.Realtime CW Signal Display 13.Input signal recording function. 14.Playback function from the file list. 15.Support the Garbage Data reduction function [Note] Since the signal after BPF is output to the audio output, it can also be used as an AF-CW filter. [URL of this App(Free version) working example video] The GUI is slightly different, but the basic functionality is the same. https://youtu.be/Pwp7W4m-m34

About

arduinoSG90

Features
Read full description

This application is for controlling the SG90 servo connected to the Arduino ESP8266 family. Therefore, an Arduiono ESP8266 and SG90 servo are required in advance, and a program must be written to the ESP8266. Please refer to the source code for program samples. This is a program that sends String data to arduino ESP8266 by UPD. Please see below for the program on the arduino side. https://ios.iya.tokyo/031udp/ If the source remains the IP address is 192.168.4.1 port 8888 I think it will be It can be operated as below https://youtu.be/M9JkJ-v0i4E

Screenshots

RST Decoder Pro4 screens
arduinoSG902 screens

Verdict

The call

The clearest difference is price: arduinoSG90 at Free against RST Decoder Pro's $1.99. arduinoSG90 also leads on update cadence (daily vs monthly). 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

CostPrice · In-app purchases · Ads · Monetization

arduinoSG90 is free to download; RST Decoder Pro costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

RST Decoder Pro ships an update monthly, arduinoSG90 daily. The most recent releases landed on October 6, 2026 and October 7, 2026 respectively.

Scorecard2 real differences · 8 level
RST Decoder Pro versus arduinoSG90: the parameters behind the verdict, then further details
ParameterRST Decoder ProarduinoSG90
Price$1.99Free — better
Rating5.0 (1 ratings) — better—
Positive reviews50.0% of reviews—
Number of ratings1 — better—
Update frequencyMonthlyDaily — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhoneiPhone, iPad — better
Requires iOS17.017.0
Further details — not scored
Size1 MB3 MB
Age rating17+4+
Developerkoji kamogawaYASUYUKI INUKAI

In-app purchases

None

RST Decoder Pro

No in-app purchases

None

arduinoSG90

No in-app purchases

Questions

Is RST Decoder Pro free?
RST Decoder Pro costs $1.99, with no in-app purchases.
Is arduinoSG90 free?
arduinoSG90 is free to download, with no in-app purchases.
Do RST Decoder Pro or arduinoSG90 have ads?
Neither RST Decoder Pro nor arduinoSG90 shows ads.
Which is updated more often, RST Decoder Pro or arduinoSG90?
RST Decoder Pro ships an update monthly, and arduinoSG90 daily. Most recently, RST Decoder Pro was updated on October 6, 2026 and arduinoSG90 on October 7, 2026.

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