[time-nuts] How can I measure GPS Antenna quality?

jimlux jimlux at earthlink.net
Mon Nov 21 18:03:12 EST 2016

On 11/21/16 10:10 AM, Tom Van Baak wrote:
>> For the equipment hobbyists usually have, the phase center is not that
>> important. Most antennas have a variation <5mm. Even 10mm would lead to
>> just a ~33ps variation.
> I agree. And besides, for those of us here in Oregon/Washington, the very ground is moving northwest at several inches per year (plate tectonics).

Is that movement in absolute terms? or relative to the NA plate?
Where I live in SoCal (on the Pacific plate side ), we also have an 
annual uplift on the order of 1cm.


For 34N, 118W, 47.67mm/yr at 297.53 degrees(CW from north) 22.04N, 
-42.28E in local coordinates

-31.57 X, 30.68 Y, 18.31 Z using WGS 84

for 34, 119W (Ventura county, some 50 miles west) 48.04mm/yr total, 
-31.12 X, 31.51 Y, 18.62 Z

A little less X, a little more Y, because it's starting to "turn the corner"

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