Hi Jason, Have a look on ebay.....280567398921..... quite good TCXO.
Rgds Ernie. -----Original Message----- From: Jason Rabel <ja...@extremeoverclocking.com> To: time-nuts@febo.com Sent: Fri, Oct 15, 2010 9:10 pm Subject: Re: [time-nuts] Discipline a rubidium driven net4501 with a Garmin LVC 18? Nothing wrong with wanting to use a Rb as the clock source for the board. I almost* decided to go that route since I had a spare PRO sitting around. But I realized that I would never need that long of old-over so it would kind of be a waste. I've been looking t some cheap ($20 USD) 1PPM TCXO on ebay... Which would be a decent upgrade rom the stock crystal rated at 50PPM. > Furthermore I'd like to get a 1PPS input from GPS as others already did. However, I would like to use one of these Garmin GPS 18 LVC units (as on http://time.qnan.org/) that usually work fine and provide a 1PPS signal together with a NMEA output and connect it to the net4501 internal serial port instead of the FatPPS (as John did: http://www.febo.com/pages/soekris/). Is there a way to get Poul-Hennings`s NTPns working with the GPS 18 as a PPS source? I'm not 100% sure, but I *think* there is a basic PPS driver with NTPns? On my ox I set the course time on boot-up via ntpdate, hen when NTPns starts it has something decent to work with (if the time is too ar off I think it throws an alarm). You can get Motorola Oncore UT+ or even M12+T receivers on eBay relatively heap. With a little effort they *will* fix inside the oekris box so you can just have a connector on the back for your antenna. The T+ receivers *will* work with NTPns. You can checkout my first build here: ttp://www.extremeoverclocking.com/articles/howto/Building_S1_NTP_Server_1.html > Is there any specific reason why a 1PPS signal from another source (like a Thunderbolt GPS disciplined clock) together with a FatPPS board would give better results as my Garmin approach? I *think* the PPS output from a Thunderbolt is not the raw GPS PPS but rather a eterministic one? Someone will have to verify / ebunk that though. However you are also kind of doubling up on the oscillators ince when a Thunderbolt looses signal it will lywheel off it's internal OCXO. I have a pre-built image of NanoBSD w/NTPns (and I think regular NTP is on there oo) that I did a while back, feel free to give it whirl: http://www.rabel.org/ntpns/ntpns_NanoBSD_7.tar.bz2 You might have to change some of the startup paramaters & ntpns configurations epending on how you wire up everything to the GPIO ins and whatnot. _______________________________________________ ime-nuts mailing list -- time-nuts@febo.com o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts nd 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.