POMO days - down dollar?

If on the POMO days, the fed is essentially buying it's own treasuries (buying its own debt), why does the dollar always drop? I can understand the printing money to buy their own treasuries but how does the FX "system" account for extra dollars in existence? If they're buying treasuries with existing dollars, then the dollar shouldn't drop at all. If it was other countries buying then you'd expect the dollar to rise.
http://www.newyorkfed.org/markets/tot_operation_schedule.html

It's spurious...

Martinghoul said:

It's spurious...

Click to expand...

In what way?
I need to look at it fully but in the past 2 weeks, every time there has been a POMO day, the dollar moves down and the market goes up practically in a straight line.
The correlation of USD against the market is a separate factor but can be viewed on stockcharts...

It's spurious in the way that spurious things normally are... You should stop listening to the conspiracy nutters.

Never really seen POMO days move USD that much. FOMC meetings are a different matter.

Oh and to answer my bet would be POMO is just reinforcing a lack of confidence in the $. But then I'm pulling that out my ****, so **** knows really.