Attila Kinali

Moin, On Wed, 17 Oct 2012 11:42:06 -0700 "Tom Van Baak" <tvb@LeapSecond.com> wrote: > > A new LEA6-T single piece cost IIRC 190EUR from the webshop. > > A LEA5-T was IIRC half price. > > > > And a little caution: the LEA5 modules use considerably more power during > > aquisition than the LEA4 did and the LEA6. IIRC we measured up to 150mA > > (compared to <100mA with LEA4). I don't know the Rasberry, but i guess > > that should be not a proble, but you should check for it nevertheless. > > I'd say the u-blox 5T or 6T is rather over-kill for George's > application, both in price and performance (and learning curve and > integration). Remember that the world of NTP is milli- and microseconds. > State-of-the-art GPS timing receivers and GPSDO are in the nano- and > picosecond accuracy/jitter range Yes, that's why i explicitly mentioned the LEA4-S, which already is way more accurate than ntp can get over the network. A LEA5-S sells for 16USD on ebay. For 30USD you already get a soldered board with an NEO6-M and patch antenna. All you need to do to use those is to solder a wire for the PPS pin and you're set. With such little money you get a top modern GPS module with high sensitivity (even the LEA4 could get reasonable indoor reception with a simple passive patch antenna, and the LEA6/NEO6 are much better) and more than good enough PPS output (<60ns w/o sawtooh correction) At these prices, i'm surprised that not more people are using the u-blox modules for their stuff. Attila Kinali -- There is no secret ingredient -- Po, Kung Fu Panda

Tom, Thank you and nice to be back! Was working major hours for a while. Workin' for a living :) Now, I must confess that this project is sort of a milestone for me. Those who hate kids (I know you are out there !) can stop reading now :) My daughter, who just turned six, has been very curious about what I do with all my machines. I have taught her how to properly solder and she can spot a cold joint and is very adamant about such things. So, I have been thinking about making a small project with lights etc. I don't have that much time and I also want to experiment with the RPI so, I can combine projects. Given that an NTP server will not be as much fun in terms of lights and so on, but I think it will be more fun when the intricacies of time are explained. She is already very interested in puzzles and stuff so I figure I'll encourage her. I was actually very sneaky with getting her interested in puzzles and stuff. You see we both love "Gravity Falls" which is this amazing Disney Channel series that has crazy puzzles in it and it is a challenge to figure out what is hiding in each episode. Using that as the start, I explained more things to her about puzzles and math and she absolutely loves it. So, to sum up (and sorry for the long post) I think an NTP server with a tiny footprint is just the ticket. Your comments are most welcome. Oh, and it would be nice to get micro-second accuracy. George, N2FGX Quoting Tom Van Baak <tvb@LeapSecond.com>: >> Question: What GPS timing module should I go with? No more Motorola >> Oncore so what's best right now? Who sell modules? What are the price >> ranges? >> >> Your comments are most welcome. >> >> -George, N2FGX > > Hi George, > > Welcome back to the list; you've been quiet for a long time. This > sounds like a great project. I hope you keep us informed with > progress and also make the results available. > > You should be able to find GPS modules with sub-microsecond 1PPS for > $25. Check sparkfun.com or the "Skylab" chip used on the > www.leapsecond.com/pages/MG1613S board. This and other chip > solutions require SMT/PCB mounting, connectors, external antenna and > cabling which can add to the net cost of complexity. > > A number of people I know who want an inexpensive, turn-key, > sub-microsecond, embedded GPS timing solution continue to chose the > Garmin 18x/LVC. These are nice because of the high-gain integrated > antenna (they work indoors), compact encapsulated design, and > extreme ease of use (5V, ground, 1PPS). > > /tvb > > >> A new LEA6-T single piece cost IIRC 190EUR from the webshop. >> A LEA5-T was IIRC half price. >> >> And a little caution: the LEA5 modules use considerably more power during >> aquisition than the LEA4 did and the LEA6. IIRC we measured up to 150mA >> (compared to <100mA with LEA4). I don't know the Rasberry, but i guess >> that should be not a proble, but you should check for it nevertheless. >> >> Attila Kinali > > Attila, > > I'd say the u-blox 5T or 6T is rather over-kill for George's > application, both in price and performance (and learning curve and > integration). Remember that the world of NTP is milli- and > microseconds. State-of-the-art GPS timing receivers and GPSDO are in > the nano- and picosecond accuracy/jitter range. > > /tvb > > > _______________________________________________ > 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. >