Ahhhh, the 28 day sma!!!! Of course. Of course. Everyone knows that. Makes perfect logic and infinite sense. But, why not the 27.12567459 day sma minus 3 toadal warts plus 5 persian cat hairs tied end-to-end ? :)
Don't disparage advice that might make up for all of those bad losses you incurred with Warren Buffet's stock. Remember? Sorry, of course you do!
Hey this smart retired independently wealthy(I listen to those folks) fisherman in Florida named John White, steered me to a number of indicators when I used to belong to an online group called ValueForum back in the '90's. Those were the 1990's. He used the 28DMA, MACD, RSI and Stochastics. This poster awhile back here wanted a simplistic system to get in and out. JW had been asked the same question you do. Why 28 days?
He had back tested it over the years and it worked. Hey, I wasn't independently wealthy, so....now you know...knowing your history here SeaD, if you place your trade with the point of your aluminum foil hat facing the North star, it is guaranteed to work every time.....good luck...;-)