[time-nuts] Expected 10 MHz offset from a GPSDO?

[Bob kb8tq]

Hi

I do not know of any commercial GPSDO's that do not have a holdover 
feature. There are a lot of variables. With a large package OCXO and a couple days 
operation, the numbers I gave should be good 90 to 99% of the time.(99 seconds out
of 100).

If the unit has such a poor antenna location that (unlike the original post) it never
completes survey, then all bets are off... The basic assumption is "locked to > 4 sats 
at all times. That generally translates to 6 or more most of the time.

Bob

Sent from my iPad

> On Aug 20, 2016, at 5:43 AM, Bryan _ <bpl521 at outlook.com> wrote:
> 
> Bob:
> With a GPSDO as a general rule is there much variation of the 0.005 to 0.02 ppb range. Would there me much if only 2 satellites were visible but the unit was no in holdover vs say 6 satellites. I assume there is probably a lot of variables such as quality of GPSDO and OCXO, multi path interference, antenna location, etc, but worse case what would a user expect assuming the unit isn't in holdover.
> 
> -=Bryan=-
> 
>> From: kb8tq at n1k.org
>> Date: Fri, 19 Aug 2016 20:03:59 -0400
>> To: time-nuts at febo.com
>> Subject: Re: [time-nuts] Expected 10 MHz offset from a GPSDO?
>> 
>> Hi
>> 
>> Ok let's toss some numbers into the mix.
>> 
>> The counter time base one day after calibration is in the 0.5 to 1.5 ppb range.
>> 
>> The LPRO ten years after it left the factory is in the 0.5 to 1.5 ppb range.
>> 
>> The GPSDO when running properly should be in the 0.005 to 0.02 ppb range at one second.
>> 
>> One ppb at 10 MHz is 0.01 Hz. It also is a the resolution limit on a 5335 at 1 second.
>> 
>> Bob
>> 
>> 
>> 
>>> On Aug 19, 2016, at 5:29 PM, Mark Sims <holrum at hotmail.com> wrote:
>>> 
>>> Try driving your counter frequency reference input with the LPRO or comparing the LPRO with the GPSDO.  The LPRO is (most likely) much more accurate the counters' internal timebase.
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