There are many scripts already published for this indicator, but I've found they didn't match the original one.
So here it is the Gann HiLo Activator as originally developed by Robert Krausz, in a 1998 article in the Stocks & Commodities magazine.
I've also added the option to select the type of Moving Average you would like to use.
Hope you enjoy!
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.