在那些不使用“线”的指标中，抛物线指标（PSAR）无疑是最受欢迎的。虽然区间交易者也以同样的方式使用，但它更受到趋势交易者的欢迎，因为可以提供给长线交易者进场和平仓的交易机会。PSAR指标从价格下面的一个点开始。PSAR的点位于价格下方的时间越长，它向上升高的速率也就越大，直到它高于价格K线的最低点。
如果PSAR开始于5根K线之前，那么它改变方位的几率是非常小的。但是如果在K线走了20~30根之后，你会发现抛物线指标的每一个点之间的距离逐渐增大。这就好像在说，趋势快要结束了，正等待反转的最后确认。
PSAR指标的点在价格的上方或者下方。当它们位于价格的下方时，当价格K线的最低点与PSAR指标点相交时，PSAR即发生反转。现在，PSAR的指标点位于价格上方。这是一个有效的卖出信号。卖出信号与买进信号的运作方式相反。你在等待一根足够高的K线接触到PSAR的点，并产生一个新的买入信号。
不论是做多还是做空，PSAR指标可以让你轻松的识别市场趋势。它所有的信号都只是在买、卖之间切换。PSAR指标历史交易中应用最好的是GBPJPY，4小时图。它可以很灵敏的反映出市场发生的巨大波动。但是，4小时图交易周期又骗短，因此，不论盈利还是亏损交易它都会在较短时间内发出平仓信号。
交易过程中，你会因为PSAR指标的延迟性而放弃很大一部分盈利空间。为此，你可以更改PSAR指标的加速度值。选择指标窗口的PSAR指标，输入窗口会显示设置步骤以及加速度。你可以通过这种方法使PSAR指标更适合您的交易风格。
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.
文章翻译由兄弟财经提供
本文来源：http://www.forexnews.com/blog/2014/07/14/trade-parabolic-sar-mt4/