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

[bg at lysator.liu.se]

With SA off, the difference between marine DGPS and stand alone GPS is not
that significant. If my memory serves me right the Monterey jammer did jam
at L1.

--

   Björn

> 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.
>>
>
>
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