Is there an EA that will take another EA's signal and make the reverse trade ? For example if the signal EA says buy the reverse EA would force a sell. I have a good EA but it goes 20 to 40 pips in DD. The mq4 file is not available.
There are trade copiers available which have that option built in.
You would have the original EA running on one instance of MT4, and the trade copier set up on another.
