On Wed, Jul 31, 2013 at 04:23:15PM +0200, Eugen Leitl wrote:

On Tue, Jul 30, 2013 at 03:18:51PM -0400, Riad S. Wahby wrote:

Is there any RF sigint at all done at the Utah site? It could all well be just a big crunch and storage facility. It would help if we had a good fiber map of the general area.

Guys, there isn't much of interest to listen to in Utah... even for NSA. Ground based RF sigint is either very local - directed at things like foreign cellphone networks or other short range VHF/UHF/Microwave comms systems that are only receivable a perhaps a few thousand feet to a small number of miles away or aimed at satellites or LF/MF/HF radio transmissions. There are only so many satellites and we have most of those of interest covered by dishes somewhere else already... and HF radio carries very little these days and optimum sites for receiving those signals are also already in place. If there is much of any RF at the facility it will likely be satellite links bringing in material of interest and maybe communicating with remote surveillance vehicles to receive their take and control their operation ... but many of the relevant satellites are not visible from Utah. And ground operations centers for those vehicles are mostly elsewhere too... By a great many many orders of magnitude the NSA take from tapping fiber world wide dwarfs almost all traditional radio reception except maybe collection of cellphone signals from platforms that perforce have to be more or less line of sight from the cellphone of interest (and therefore not in Utah). Most radio propagation is line of sight. Quite hard for a ground based facility to receive much from other ground based transmitters for more than a relatively few miles (easily less than around 100).

I suspect that the NSA is doing a lot of decentral signal prefiltering and processing at the network edge, and only uses large central facilities if they're unavoidable.

They HAVE to limit the edge take and filter, too much to deal with otherwise. -- Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either."