[time-nuts] Delay through GPS antenna splitter/amplifier -- an answer, and a question

[John Ackermann N8UR]

In short, yes.  If you want true traceability to NIST, you need to take 
into account UTC(GPS) versus UTC(NIST).

I don't think you would do this by adjusting the cable delay, because 
that offset will change over time.  Instead, you post-process by getting 
the offset for the time during which you made the measurement, and 
adding it to your solution.

John
----

Jason Rabel wrote:
> Since we are on the subject... I came across this page the other day and am
> curious about what other's thoughts are about it.
> 
> http://tf.nist.gov/service/gpstrace.htm
> 
> If I understand correctly looking at the graphs, they are saying the time
> from GPS is currently off about 24-30ns from the NIST frequency standard. So
> does that mean that a person wanting every last ns should adjust their delay
> according to the data on that page (and of course things like cable delay
> and other circuitry)?
> 
> Jason
> 
>> But we're time-nuts... we DO worry about those things. :-)
>>
>> While we were at it with the network analyzer, we did FDR (frequency 
>> domain reflectometry) to measure the cable delay to the antenna, and I 
>> spent yesterday making up six matched cables to go from the splitter to 
>> the receivers -- they all test within about 1 nanosecond of each other.
>>
>> Obsessive compulsive?  Me?
>>
>> John
> 
> 
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