在那些不使用“線”的指標中，抛物線指標（PSAR）無疑是最受歡迎的。雖然區間交易者也以同樣的方式使用，但它更受到趨勢交易者的歡迎，因為可以提供給長線交易者進場和平倉的交易機會。PSAR指標從價格下面的一個點開始。PSAR的點位於價格下方的時間越長，它向上升高的速率也就越大，直到它高於價格K線的最低點。
如果PSAR開始於5根K線之前，那麼它改變方位的幾率是非常小的。但是如果在K線走了20~30根之後，你會發現抛物線指標的每一個點之間的距離逐漸增大。這就好像在說，趨勢快要結束了，正等待反轉的最後確認。
PSAR指標的點在價格的上方或者下方。當它們位於價格的下方時，當價格K線的最低點與PSAR指標點相交時，PSAR即發生反轉。現在，PSAR的指標點位於價格上方。這是一個有效的賣出信號。賣出信號與買進信號的運作方式相反。你在等待一根足夠高的K線接觸到PSAR的點，並產生一個新的買入信號。
不論是做多還是做空，PSAR指標可以讓你輕松的識別市場趨勢。它所有的信號都只是在買、賣之間切換。PSAR指標歷史交易中應用最好的是GBPJPY，4小時圖。它可以很靈敏的反映出市場發生的巨大波動。但是，4小時圖交易週期又騙短，因此，不論盈利還是虧損交易它都會在較短時間内發出平倉信號。
交易過程中，你會因為PSAR指標的延遲性而放棄很大一部分盈利空間。為此，你可以更改PSAR指標的加速度值。選擇指標窗口的PSAR指標，輸入窗口會顯示設置步驟以及加速度。你可以通過這種方法使PSAR指標更適合您的交易風格。
How To Trade The Parabolic SAR in MT4
Shaun Overton
The Parabolic SAR is far and away the most popular indicator that doesn’t use lines on the chart. It’s used by range traders and trend traders alike, although it’s widely used by trend traders. The indicator provides long term opportunities by spotting entry and exit signals.
The Parabolic SAR starts with a dot underneath the price. The longer that the dot remains underneath the price, the dots move exponentially races to catch up with the individual bar lows formed in the market.
If the Parabolic SAR started only 5 bars ago, the rate of change between the dots is very small. But as you get 20-30 bars into an opportunity, as you see here, the space between each successive dot increases rapidly. It’s like the PSAR is saying this trend has got to end soon. It’s waiting for the final bit of confirmation to flip direction.
The dots on this chart are either above the price or below the price. When they start below the price, the moment that they flip is when this low touches the dot formed on the last bar. At the precise moment when the bar’s low touches the PSAR value on the last bar, the dot flips.
The dot is now above the price. That is a valid sell signal. The sell signals work in the opposite way to the long signals. You’re waiting for a bar high to touch the dot and create a new buy signal.
The indicator gives you an always in the market reading, either long or short. All of the signals alternate purely back and forth between buy and sell signals.
The way to use this in a trending strategy is as basic as the indicator. Buy when the dot flips below the price. Sell when the dot flips above the price.
The best Parabolic SAR strategy that I’ve seen historically is the GBPJPY H4 chart. That currency pair is prone enough to trends to generate signals with substantial volatility. But, the four hour time frame is short enough that it’s able to exit trades, both good ones and bad ones, in relatively short order.
You do give up substantial ranges on profitable trend trades by waiting for the dots to catch up. There’s not much that can be done about that except by playing with the PSAR acceleration values. You can do that by left clicking on the chart and choosing indicators, then Parabolic SAR. The inputs window shows the step and acceleration, which you can play with to suit your trading style.
文章翻譯由兄弟財經提供
本文來源：http://www.forexnews.com/blog/2014/07/14/trade-parabolic-sar-mt4/