NED data in GridFloat format
From PathlossWiki
This is the same NED data except in Grid float format. These files are twice as big as the BIL format. They will run a bit slower for generating network backgrounds.
Links to Prepackaged GridFloat files. Each file is 1degree X 1 degree and is named by the north west corner.
1" GridFloat files:
ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/NED/1/GridFloat/
1/3" GridFloat files:
ftp://rockyftp.cr.usgs.gov/vdelivery/Datasets/Staged/NED/13/GridFloat/