[FedCom] New antennas on the Secret Service suburban

[john wilson]

    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.
> >
> >
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>
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