200 Day MA Volatility Band - Help Needed to construct

I am looking to form a "Bollinger like" Band whereby:
1) The center of this Band is the 200-day moving average of a stock symbol, say SPY.
2) The top of the Band is calculated by adding one standard deviation of normal volatility of the SPY (in this case) to the 200-day moving average.
3) The bottom of the Band is calculated by subtracting one standard deviation of normal volatility from the 200-day moving average.

And just to be clear, I could not accomplish the abobe with an actual Bollinger band.

Many thanks in advance.

Comments

  • markd
    markd mod
    edited February 2020
    I'm not sure why you can't change the default parameters to your requirements - from 20, 2.0 to 200, 1.0




    - but if that doesn't work for you, your alternative would be to create a user defined index (UDI) in a spreadsheet by downloading the "Past Data" file and loading it into your spreadsheet for calculation, then uploading the resulting data.

    User-defined indexes are explained here:

    https://support.stockcharts.com/doku.php?id=data:user-defined_indexes