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Discussion of precise time and frequency measurement

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Re: GPSDO - GPS1300-10-1000 by RFX Ltd. UK

DK
Dan Kemppainen
Wed, Mar 2, 2022 6:51 PM

On 3/2/2022 12:40 PM, time-nuts-request@lists.febo.com wrote:

Lady Heather was on my 'to buy' list so it sounds as though I should get her now and a cheap GPS brick to see what the viewing is like. I have a couple of old M12 eval modules from back in the day that were never switched on and a couple of uBlox LEA-M8T-0-10 modules chopped out of Huawei PCBs by the Chinese, but it will probably be quicker and easier to get a cheap module as you suggest. My electronics Lab faces South so I can sit one of the small patch antennas that came with the Motorola kit on the window ledge for initial trials before climbing on the roof.

Just a quick heads up, Lady Heather has a bug in it when it comes to
Ublox GPS Modules. Sometimes sats are displayed where they are not.

The details are a bit fuzzy off the top of my head (and I'm not at the
home lab where the data is). What happens is that sometimes the Ublox
modules report an SV, with blanks for signal strength and az/el values.
Those unpopulated values cause the next set of values to be read
incorrectly for the given SV.

See F9P.jpg. See the arc of light blue into the circle of no birds near
the top? That shouldn't be there.

I believe the bug is something that should easily be fixable. After a
day or so of struggling to get set up to complete LH, I found more
important stuff to take care of...

If anyone is willing to look into fixing this bug, TVB and I have some
details on where to look, and some test data to use. I'd really like to
see it fixed, but am not really the guy to tackle the problem. I'll
gladly help guide anyone willing to look into the bugfix.

Dan

On 3/2/2022 12:40 PM, time-nuts-request@lists.febo.com wrote: > > Lady Heather was on my 'to buy' list so it sounds as though I should get her now and a cheap GPS brick to see what the viewing is like. I have a couple of old M12 eval modules from back in the day that were never switched on and a couple of uBlox LEA-M8T-0-10 modules chopped out of Huawei PCBs by the Chinese, but it will probably be quicker and easier to get a cheap module as you suggest. My electronics Lab faces South so I can sit one of the small patch antennas that came with the Motorola kit on the window ledge for initial trials before climbing on the roof. > Just a quick heads up, Lady Heather has a bug in it when it comes to Ublox GPS Modules. Sometimes sats are displayed where they are not. The details are a bit fuzzy off the top of my head (and I'm not at the home lab where the data is). What happens is that sometimes the Ublox modules report an SV, with blanks for signal strength and az/el values. Those unpopulated values cause the next set of values to be read incorrectly for the given SV. See F9P.jpg. See the arc of light blue into the circle of no birds near the top? That shouldn't be there. I believe the bug is something that should easily be fixable. After a day or so of struggling to get set up to complete LH, I found more important stuff to take care of... If anyone is willing to look into fixing this bug, TVB and I have some details on where to look, and some test data to use. I'd really like to see it fixed, but am not really the guy to tackle the problem. I'll gladly help guide anyone willing to look into the bugfix. Dan