[time-nuts] The Demise of LORAN (was Re: Reference oscillator accuracy)

[Didier Juges]

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: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] 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.
>