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 Från: Gedas<mailto:w8...@mchsi.com> Skickat: den 14 mars 2016 20:00 Till: Discussion of precise time and frequency measurement<mailto:time-nuts@febo.com> Ämne: Re: [time-nuts] BG7TBL GPS Disciplined Source Hi Hal, and TU for the reply. Tu also to everyone else with the very helpful hints and info. Following the advice of Joe I checked out the EEV Blog site.....very good information about the different variants of this maker. Turns out, because I have a model (date code) of 2014-12-09 that it corresponds to this revision and information: custom board with surplus russianmorion mv89 <http://www.morion-us.com/catalog_pdf/MV89.pdf>OCXO. gps isu-blox NEO-6M-0-001 <https://www.u-blox.com/en/product/neo-6-series>. Who would have guessed a Russian OCXO. And, I guess the U-Blox is not one of the better GPS units based on what Paul mentioned. But I think there is software out there that will let me at least monitor what my unit is doing and how many birds it is receiving data from. I also have the 8-port signal splitter which is nice as I can now run my reference to all my various TE. Oh well, it is what it is as I do not have the money to purchase a different one. To answer your question I am using the supplied "hockey puck" style antenna placed outside my basement window well, sitting on a small wooden shelf, but close to ground level. The antenna should have a clear view from 90-280 degrees, from an elevation angle of 0-90 degrees. Anything from West to North to East (~280-90 degrees) is blocked by the house. I guess my next step, as Bob suggested will be to install some monitoring software to see how many birds I am able to see on average. Gedas, W8BYA Gallery at http://w8bya.com Light travels faster than sound.... This is why some people appear bright until you hear them speak. On 3/14/2016 12:55 AM, Hal Murray wrote: > w8...@mchsi.com said: >> This is where I really embarrass myself.....sometime ago I purchased an >> inexpensive 10 MHz GPS based reference source (BG7TBL GPS Disciplined >> Source) for my various counters, transceivers, spectrum analyzers, etc and >> was wondering if it was a good purchase and if anyone else used a similar >> unit. I guess in the end I am curious to know what the short & long term >> accuracy and stability of my unit may be? I no longer have access to any >> accurate (known) frequency sources like I did while employed and I do not >> think I have the equipment here at home to measure my unit myself. > Long term accuracy will be very good - you are tracking GPS. > > You didn't say anything about your antenna. That's probably the major > contributor to your short term accuracy. > > Google found: > http://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/ > Looks like there are various versions. > > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.