[time-nuts] Common-View GPS Network

[Jim Lux]

On 4/15/13 10:40 PM, bg wrote:
> Chris,
>
> Chokering is not needed.  Measured quality antennas are listed at
>
>       http://www.ngs.noaa.gov/ANTCAL/
>
>   Or at
>
>        http://www.geopp.de/index.php?sprachauswahl=en&bereich=0&kategorie=34&artikel=62
>
> /Björn
>
>
>

A lot of the antennas on that list are choke ring type.  If you are 
doing geodetic work, millimeter scale changes in phase center are 
important.  For time transfer, maybe not.. 1mm is 3 ps, after all.

A ratty old patch antenna has a phase center variation of a few cm at 
most, and that's 30-50 ps.

the effect of a strong multipath (which is what the choke ring 
suppresses) would be a LOT bigger than that..