[time-nuts] Re: What time difference to expect from two clocks using internal GPS receivers?

[Dan Kemppainen]

Hi,

Have you looked at the delay of the GPS signal passing through the 
filter to the one unit vs C on the other?

I've seen a similar situation where a bias T was the culprit. I don't 
recall the numbers off hand but it was significant enough to notice, and 
the difference went away once the T removed (or duplicated on the other 
device).

Dan


On 5/1/2022 3:30 AM, time-nuts-request at lists.febo.com wrote:
> 
> Some more info
> The two GPS do keep their phase stable vs a Rb within ±10 ns. But the
> absolute time difference of their PPS pulses  was, after a cold start,
> stable within ± 20ns but  the average value could be up to 100ns and
> differed after every cold start.
> The two GPS antenna cables had a length difference of 1 meter, but that
> should cater for only 5 ns (?) One module is connected to the antenna with
> only a C, the other has a 1 GHz CLC high pass filter between antenna and
> module
> Erik