John: I missed this on its intro to the group. Great paper and effort.
It's also a very useful intro/primer to measurement methodology beyond
application to only the u-blox family. Thanks for leveraging the NSF for
our benefit!
Don
On 2021-08-28 05:02, Julien Goodwin wrote:
On 24/8/21 11:51
On 24/8/21 11:51 am, John Ackermann N8UR wrote:
> In 2020 I did an extensive evaluation of the timing ability of the
> u-blox LEA-M8F, NEO-M8N, NEO-M8T, NEO-M9N, ZED-F9P, and ZED-F9T. The
> work was made possible by support from the HamSci consortium
> (https://hamsci.org) under NSF grants
Hi Andrew --
Yes, it's entirely possible the problem was with the setup. I doubt it was
signal level (I was feeding clean 3.3V TTL PPS signals) but I'm not sure that
my data capture software was as robust as it could have been.
John
On Aug 25, 2021, 5:16 PM, at 5:16 PM, Andrew Rodland
Very interesting.
When I built my Arduino Due-based Rb clock (currently disassembled) around
a NEO-M8T (more specifically, an EVK-M8T), I used the EXTINT to measure the
difference between my onboard PPS and the GPS top-of-second. I ran it
pretty long term without seeing any lost or duplicated
On 24/08/2021 02:51, John Ackermann N8UR wrote:
In 2020 I did an extensive evaluation of the timing ability of the
u-blox LEA-M8F, NEO-M8N, NEO-M8T, NEO-M9N, ZED-F9P, and ZED-F9T. The
work was made possible by support from the HamSci consortium
(https://hamsci.org) under NSF grants supporting
Hi,
I hope you don't mind me starting a "newcomer" thread based on your
sentence: "with a GPSDO, finding one that’s got a clean output is not at
all easy".
Are there any up-to-date resources that would provide such information
about a larger selection of GPSDOs?
Are there any GPSDOs that people
Hi
The simple answer is to put a cleanup loop on the output of the GPSDO
if you are looking for a low noise signal. In the microwave case, something
running at (maybe) 100 MHz with a good OCXO is a pretty bulletproof
solution.
Indeed, if you need low phase noise at 10 MHz, the same basic
Thanks very much, John.
Dana
On Mon, Aug 23, 2021 at 8:52 PM John Ackermann N8UR wrote:
> In 2020 I did an extensive evaluation of the timing ability of the
> u-blox LEA-M8F, NEO-M8N, NEO-M8T, NEO-M9N, ZED-F9P, and ZED-F9T. The
> work was made possible by support from the HamSci consortium
>
Hi
The problem with the approach used in the basic GPS / GNSS modules is
that the TCXO is not tuned on frequency. Even with an integer relation to the
internal oscillator, you still see the pulse drop / pulse add into the divider.
The
result is that they are noisy.
There are a couple of modules
Hello,
thank you for sharing valuable comprehensive comparisions.
In the high timepulse rate experiment, have you also investigated other rates
than the standard 10 MHz? Most Ublox receivers use 48MHz internal clock thus
the 10MHz timepulse must be missing some of the clock pulses which
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