[time-nuts] Frequency Ensemble

[Michael Wouters]

The f9p is about 3 times better than  the ublox m8t. Will post a plot
later..

Cheers
Michael

On Tue, 19 Mar 2019 at 9:00 am, Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> ….. and here I was wondering if it had ever gone out :) Glad it made it.
>
> No, I did not run any single frequency units beside it. It is much better
> than any similar plot
> I’ve done in the past on an L1 only part.
>
> Indeed, as long as you just look at the first ~ 100 seconds, the
> “reference standard” is less of an issue.
> A fairly typical OCXO will hang in there at 2 ppt or so out to a couple
> hundred seconds.
> You can get a very good idea of what’s what simply by going out that far.
> Indeed you might spend
> some “quality time” finding a working example of something like a MT-260.
> That’s part of the fun ….
> Some of the better parts will be 5 MHz units. A HP 5335 can come in handy
> to turn 5 MHz into
> 10 MHz ….. there are a lot of ways to get that done.
>
> Yes LH and a TAPPR TICC would also help in the process …. still need those
> 25 orders :)
>
> Bob
>
> > On Mar 18, 2019, at 3:29 PM, Dan Kemppainen <dan at irtelemetrics.com>
> wrote:
> >
> > Bob,
> >
> > I recalled the plot you posted a few days ago. Nice plot on the F9P,
> BTW. Thanks for posting that.
> >
> > I don't supposed you happened to be recording a similar plot with a L1
> only Ublox part at the same time by chance, did you? I think it would be
> interesting to compare a 6T or M8 part to the F9P. (I lack a standard good
> enough to compare them to...)
> >
> > Thanks!
> > Dan
> >
> >
> >
> >
> > On 3/18/2019 1:00 PM, time-nuts-request at lists.febo.com wrote:
> >> Message: 2
> >> Date: Mon, 18 Mar 2019 12:26:55 -0400
> >> From: Bob kb8tq<kb8tq at n1k.org>
> >> To: Discussion of precise time and frequency measurement
> >>      <time-nuts at lists.febo.com>
> >> Subject: Re: [time-nuts] Frequency Ensemble
> >> Message-ID:<88460EA2-6034-48D1-A77A-FED1F824D843 at n1k.org>
> >> Content-Type: text/plain;    charset=utf-8
> >> Hi
> >> There are a variety of GPS devices that put out a PPS. uBlox makes
> some, there
> >> are a number of other companies that do so. The PPS comes out modulo
> the local
> >> timebase. On a precision part, there is a ?sawtooth correction? message
> that also
> >> comes out to further quantify the best guess time of that pulse.
> >> Noise wise, even with correction you are lucky to get a one second ADEV
> in the
> >> 1 to 2 ppb range with a typical L1 receiver. With a L1 / L2 device like
> the F9P,
> >> you might do a bit better than that.
> >> The ADEV of your other sources at short tau will be much better than
> the GPS PPS
> >> noise. As you average out over long periods, the GPS will win the race.
> >> Bob
> >
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