Have you seen the Solar version of the 1090?
WS-1090-SOLAR WIRELESS HOME WEATHER STATION w/ SOLAR POWERED SENSORS ATOMIC TIME | eBay
Don't need any batteries for the outdoor unit?
One nice thing I heard about the WS-1170 (& 1171) unit,
is the Time receiver is out there inside the outdoor module..
Meaning it's going to clear of a lot of computer & other RF noise inside the house..
Maybe more accurate time setting!!