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#gotcha — Public Fediverse posts

Live and recent posts from across the Fediverse tagged #gotcha, aggregated by home.social.

  1. About metrics for measuring agreement on regression on continuous datasets:
    Reasons to avoid R² and use RMSE instead: feat.engineering/03-Review_of_

    From Max Kuhn @topepo, Kjell Johnson (2026), "Feature Engineering and Selection: A Practical Approach for Predictive Models"

    #prediction #dataDev #modelEvaluation #regression #modelling #linearRegression #modeling #probability #probabilities #statistics #stats #gotcha

  2. Aircraft and glider transponder codes - FAA gotcha.

    I have not yet received my glider registration from the FAA (any day now, lol!), but they have assigned a transponder code for the N-number I have reserved. (see first screenshot)

    To configure my avionics, I need to load this transponder code into the device.

    FLARM wants it as a 24-bit hexadecimal value. (Each hexadecimal value is 4 bits in binary...so it's going to be a six-character code...but my code is not six characters.)

    Hmmmm, that number the FAA gave me just doesn't seem correct.

    I then called up a known, long-registered aircraft to compare their transponder code. (2nd screenshot)

    Surprise! The transponder code I was given was in octal, but not labeled as such. OK, convert to hexadecimal and now everything makes sense.

    Onward!

    #AvGeek #Aviation #ElectricAircraft #ExperimentalAviation #Homebuilt #Glider #DIY #Avionics #Electronics #Transponder #Octal #Hexadecimal #Gotcha #FAA