RST Decoder Pro 4+

Audio Morse code Decoder

koji kamogawa

    • 5.0 • 1 Rating
    • $1.99

iPhone Screenshots


Simple Morse Decoder App for CW Beginner
It is a Morse practice App that you can use to check if you are keying the correct code.

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
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

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.

What’s New

Version 2.0.0

I reviewed the parameter of the decoder part and improved the performance.

Ratings and Reviews

5.0 out of 5
1 Rating

1 Rating

WMcG1775 ,

No good

As a Licensed HAM operator I have to say this is no good for decoding Morse much less anything!!!!!!

Developer Response ,

I am very sorry for your bitter evaluation. I understand and explain when this decoder doesn't always work, and I also provide a free version of the software to check. However, I would like to continue studying software improvements, even if little by little.

App Privacy

The developer, koji kamogawa, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More


  • Family Sharing

    Up to six family members can use this app with Family Sharing enabled.

More By This Developer

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