The sniffers we have been talking about are for the DHS contract. Grummans devices did not hold up during multiple field testing by DHS. PSID's did however. Go to DHS site for the memos about this.
YOu are correct about the times. Grummans device, which does not operate consistently in field testing, has a 36 hour rate while PSID's is 6 hours. PSID has stated they expect to drop this time to 30 minutes which really is needed. By the time Grummans device detected, it would be too late for people I am afraid. Good post Rob.