[time-nuts] Allan Deviation -> more data: GPS 1PPS against OCXO/128

[Poul-Henning Kamp]

In message <4543777E.9060104 at ispwest.com>, kd7ts writes:
>Didier Juges wrote:
>> There are sudden increases in noise (bursts that last from seconds to 
>> minutes) on the plots I posted.
>> 
>> I believe the sudden and drastic increase in noise at times comes from 
>> the GPS loosing lock. At the moment, I cannot hook up the computer to 
>> the GPS and verify, but I will do that later.
>
>--------
>
>I have a Brooks Shera GPSDO that exhibited similar symptoms. 
>The phase showed huge jumps around 4:00 - 4:30 every 
>morning.

This is very likely the effect of low elevation signal reflections.

Try setting the mask-angle of the GPS receiver higher.

The jumps happen when a satellite is added to or removed from the
ensemble but is affected by a large amount of ionospheric delay.

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