I think the problem with the Monterey Bay jammer was that he was jamming the DGPS correction signal, not the GPS signal itself. The DGPS correction signal is sent over the UHF band. Most marine GPS are DGPS because they need the better resolution it provides, particularly to find buoys and channel markers in the fog. The DGPS correction signal does not benefit from the spread-spectrum modulation and associated jamming resistance of the GPS signal itself.
Didier > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Hal Murray > Sent: Sunday, November 15, 2009 6:30 PM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] The Demise of LORAN (was Re: > Reference oscillator accuracy) > > > Jamming Range : Average 40 meters radius Output Power : > Total 6.5 > > Watt > > > ratio : 40/6.5 = 6.15 meters/watt > > Isn't received power 1/R-squared? > > I think those calculations should be radius-squared/watts > > > I find it interesting that the products designed as jammers > have ranges of "only" a few 10s of meters while a recent > message here said 1/2 mile from a digital-radio link that was > transmitting on 315 MHz. (aka designed for something else > rather than as a jammer) > > Similarly, the Monterey Bay jammer wasn't trying to be a > jammer, and it wiped out a huge area. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
