Sorry, a repost of six month's ago information:

-Caution...blatant commercial hucksterism follows:
-
-We've found a source for ACTIVE GPS antennas that are WATERPROOF, GASKETED,
and
-mount in a single 7/8" (22mm) hole. They come with 16.4 feet (actually, 5
-meters) of tiny little RG-174 cable and your choice of BNC, TNC, or SMA crimp
-connectors. Color of the antenna is white and about 3" in diameter.
-
-Two models, same EXACT physical specifications:
-
-8715 -- 25 dB gain, moderately good filter, and 12 mA of current draw. $
67.50
-
-8776 -- 26 dB gain in two stages with an excellent interstage filter to cut
out
-some of that VOR receiver interference we've heard about. Same 12 mA of
current
-draw. $ 87.50
-
-Plus $ 7 for USPO shipping to the USA.
-
-Included is the famous RST installation and service manual, and a one-year
-factory warranty. The installation and service manual will also detail how to
-build a GPS ground plane for a plastic/wood aircraft.
Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com