$DXY

The U.S. Dollar Index weekly chart is triggering a 3d long signal, but price has yet to move.  In anticipation of the weekly triggering the 3d long we can watch the daily and look to enter on the fast line going green (which it did on Aug. 5th rendering your entry under water for the time being) or we can wait for more solid confirmation. 

Just because the signal "didn't work" right away doesn't mean there's not potential opportunity.  Often times a signal failure could be hinting at a potential roll-over in price, as it did back in Feb. 2008.
The chart below shows a "safer" way to enter by letting price prove itself rather than relying on the daily 3/10macd fast line for entry.  In such a case we would be looking for a break of the range which price is in, so we have a 3d long entry on the weekly but price isn't breaking out of its upper range, suspecting a roll-over we can look to get short as price approaches or goes through it's lower range.

Here's a look (chart below) at the second 3d setup of that year in July.  We had the weekly setting up a 3d long entry and the fast line turns green on the daily 'triggering' a long entry for that weekly signal.  Otherwise, you could wait for the breakout of the upper range as occurred at the beginning of August that year.

Back to the current setup.  Keep an eye on the upper/lower ranges.  Price is coiling and something has got to give, whether price rolls-over or breaks higher is less important than waiting for price to prove itself.