[ntp:questions] Questions about joining pool.ntp.org

Brian Utterback brian.utterback at oracle.com
Sun Aug 28 20:25:45 UTC 2011

On 08/28/11 11:23, David J Taylor wrote:
> "Brian Utterback" <brian.utterback at oracle.com> wrote in message
> news:4E5A2A83.6030006 at oracle.com...
> []
>> According to the FCC info, the problem is due to old GPS units not
>> sufficiently filtering out the adjacent bands that were previously
>> empty. Since the bands are currently empty, I am not so sure that it is
>> only older units.
>> so, does anybody know if the Sure units are susceptible to this problem?
>> -- 
>> blu
> The impression I got was that 95% of current GPS units might be
> affected. Hand-held, car "sat nav", and many other systems.
> Putting anything powerful and widespread next to a weak-signal satellite
> band in use by consumer appliances is just plain crazy planning, in fact
> it's a complete lack of planning!  IMHO.

There are two sides with different figures. The GPS industry says that
500,000,000 units would be affected. The company LightSquared says it is
really 200,000. The DOD standards for GPS receivers issued in 2008 says
that devices should require no more than a 4 MHz gap between bands, and
LightSquared is allowing a 23 Mhz gap, but GPS manufacturers say that
they need a 34 Mhz gap. Further, the DOD warned GPS manufacturers in
2000 that they were not sufficiently selective.

Ouch. The GPS manufacturers took short cuts, and just like the Netgear
fiasco, there are millions of units that will be affected with no way to
fix them. And it is the users that are going to get hit.

Interestingly, the FCC has said to both LightSquared and the GPS
industry to cut the BS and come up with the real figures.


Always code as if the guy who ends up maintaining your code will be a
violent psychopath who knows where you live. - Martin Golding
Brian Utterback - Solaris RPE, Oracle Corporation.
Ph:603-262-3916, Em:brian.utterback at oracle.com

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