[FedCom] New antennas on the Secret Service suburban

[Ron Cluster]

Actually it is possible that several different mapping programs could have
that same error. I have noticed identical errors in Precision Mapping and MS
Streets and Trips. There are very few choices available for the base data
that commercial mapping programs use so if they all use the same base data,
and that base data has that error, they will all end up with it. I doubt
that any of the commercial mapping programs actually do their own surveying,
they use the data made available by the government.

Ron in Eugene


-----Original Message-----
From: fedcom-bounces at mailman.qth.net
[mailto:fedcom-bounces at mailman.qth.net]On Behalf Of john wilson
Sent: Tuesday, August 10, 2004 9:23 AM
To: Discussion of Federal Government Communications
Subject: Re: [FedCom] New antennas on the Secret Service suburban


    I also have a Garmin V.  I live near a military installation with an
interstate connection highway relatively close to one side for a few miles.
For a certain distance  of approximately 1-2 miles I and a few other ham
radio
locals using GPS receivers/mapping programs have noticed a phenomenon.  The
GPS receivers  have no problem acquiring satellites but the  mapping program
display GPS tracking graphic executing on a laptop in the vehicle will be
noticeably off for that stretch of road.  This occurs when using Mapsource,
Street Atlas 2003 and Street Atlas 8.  I am not the only one locally
experiencing this occurrence and I doubt that all the mapping programs would
have the same problem.  This erroneous display occurs only in this one area
and there is no RFI source nearby.  At a particular location on the
interstate
the GPS tracking graphic returns to a dead on display of the road which is
the
typical occurrence.

  The local consensus is there is a built in GPS error for these selected
latitudes and longitudes locations.  I think it is possible for GPS software
to be programed for such situations.  We all know that there is a deliberate
in error for the GPS downlink signals.  It is conceivable and possible that
for selected latitudes and longitudes additional GPS built in errors could
be
programed.  Currently piloted aircraft have no problem compensating with the
built in error or with the add on interface that reduces the error.



bernieS wrote:

> curiously, my Garmin GPS-V failed to get a fix on *any* GPS satellites
> during a public outdoor POTUS speaking engagement (it was fine before
> and afterwards...)
>
> can anyone else verify this phenomenon?
>
> On Sun, 8 Aug 2004, MONIX wrote:
>
> > Take your service monitor or spectrum analyzer.
> >
> > >>This makes more sense, and jamming has worked recently to
> > >>protect Principals from command detonated threats until the
> > >>convoy has passed.<
> >
> > >That's a very interesting suggestion. The POTUS will be in my area next
> > >week, so we'll have to see if it shows up here.
> >
> >
> > _______________________________________________
> > FedCom mailing list
> > FedCom at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/fedcom
> >
>
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