• Data on Cassette via minimodem 0.24 on macOS 10.15.1

    From Prof. Justin@alt.ei-04dws6g@yopmail.com to alt.ham-radio on Wed Dec 4 09:44:39 2019
    From Newsgroup: alt.ham-radio

    Using minimodem on macOS I'm trying to recreate this just to see how
    much I can save on a C60 cassette. I'm aware of the kansas city
    standard - I'm not using that because I can't find anything modern that
    will support it.

    minimodem is for HAM radio, but I have had good luck recording data at
    2400 baud. I wondr if I can go faster.

    cat file.txt | minimodem -t 2400 -f file.txt.wav or flac

    produces a sound file that i record to tape. Then I play back the tape
    and capture the audio via a line-in or aux cable to another wav.

    minimodem -r 2400 -f file.txt.wav > out.txt

    My results were inconsistent. Sometimes I was able to get the original
    data file from the audio file capturtes from the analog source -
    sometimes I wasn't.
    Then I discovered it wasn't hot enough. I used Audacity's amplify
    effect and was able to successfully decode the original file from the
    analog capture at 1200 baud. Then I went to bed.
    I need to increase the volume from the cassette player to the laptop.
    I think 2400 baud might actually be possible at this point.

    https://imgur.com/WE9MVQJ

    minimodem isn't on macports, only via Homebrew.

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