[time-nuts] BG7TBL GPS Disciplined Source

John Miles john at miles.io
Mon Mar 14 18:42:12 EDT 2016


My understanding from someone who has purchased one recently is that the frequency offset error was indeed just a bug, and that it's now fixed.  I've added a note to the end of my page at http://www.ke5fx.com/gpscomp.htm to that effect.

If the bug has been fixed (or the algorithm replaced), and if you get one with a good MV89A OCXO, the BG7TBL GPSDO has the potential for decent performance.  In principle all of the right ingredients are there... it's just a question of whether the software is making the most of them.

-- john, KE5FX
Miles Design LLC


> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Lars
> Walenius
> Sent: Monday, March 14, 2016 12:41 PM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] BG7TBL GPS Disciplined Source
> 
> Hi
> 
> If you are lucky the MV89 might be a very good OCXO and U-Blox makes very
> good GPS modules. The NEO-6M is not the best as it isn´t a timing module. But
> in your GPSDO the GPS module with an external antenna is not the limiting
> factor but more the controller and it´s limited resolution on the time
> measurement that is larger than the ripple from the GPS module. Also the
> software with FLL seems to limit the performance a lot. But with the long time
> constant the frequency accuracy, even with the offset due to the FLL, will be
> quite good.
> 
> U-blox own software uCenter have worked well for me.
> 
> Lars



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