Hi David Aside from in the Jupiter itself the Zodiac chipset was widely used in GPS navigational receivers and, just for example there's one that's possibly similar to yours, albeit marked ZOD1, shown here.... http://www.gpsnuts.com/mygps/gps/hardware%20reviews/randmcnally/rand_mcnally _gps.htm I assume you're aware that although the 1PPS and 10KHz were themselves locked together in most, and possibly all, versions of the Jupiter, in the earlier versions, at least up until firmware 1.03, these weren't in sync with UTC. Later versions, 1.50 for example, were in sync but other "settling down" issues have resulted in version 1.80 being generally accepted as the earlist "fully stable" release. However, in this instance I suspect what you've got is far enough removed from a Jupiter that the firmware is different and that 1.83 firmware version number is probably just an unfortunate coincidence. What you're seeing exactly describes the situation in the earlier Jupiters so it would seem likely that 1 PPS and 10KHz just aren't synchronised to UTC in these either. Regards Nigel GM8PZR In a message dated 28/07/2013 00:23:42 GMT Daylight Time, [email protected] writes:
The Jupiter (TU-30) board in my homebrew GPSDO has died. A friend gave me some unmarked Jupiter-like boards with Conexant chips that he had been told were Jupiter compatible. The boards are mounted on an aluminium plate that has a puck-type antenna on it. One of the chips has a sticker with ZOD8 V1.83 printed on it. The boards have the same connections as a Jupiter, and I've been able to connect one to my GPSDO in place of the dead Jupiter. It eventually starts outputting sensible messages with location etc. and the homemade display on the GPSDO shows that everything is supposedly normal. However, the PLL will not lock. Even though there's 10 kHz from the board (which I can only measure to 1 Hz accuracy), the PLL keeps hunting for lock. The 10kHz is in sync with the 1pps also from the board. However, when I compare the 10kHz to 10 MHz from another GPSDO, it doesn't appear synced to GPS - it must only be fractions of a Hz off, though. At the moment, I'm thinking there are 3 possibilities: - I need to send a command to the board to configure the 10kHz/1pps somehow. The Jupiter doco doesn't show any command like that and seems to assume the 10kHz and 1pps are always there. - There are components for the 10kHz/1pps syncing missing. I've already had to add a jumper wire where bits for supplying active antenna power were missing (from factory). - The firmware doesn't support 1pps / 10kHz. Perhaps the boards were meant for navigation only. Does anyone recognise these boards and have experience with extracting 10kHz from them? Regards, David Smith _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
