The pulse from my T-Bolt is on the order of 1uS wide. I captured it on the digital scope for posterity and future reference.
http://www.fastbobs.com/pictures/1pps.jpg Bob On Mon, Jul 23, 2012 at 12:58 PM, Chris Albertson <albertson.ch...@gmail.com > wrote: > I wass fooled by this too. My analog scope does not sync on athe1Hz > pulse. You have to breadboard something that will detect it, maybe a > flip flop and then look at the FF's output. > > On Mon, Jul 23, 2012 at 9:49 AM, Azelio Boriani > <azelio.bori...@screen.it> wrote: > > ...And don't forget that the PPS pulse is very narrow so you have to use > a > > 'scope with memory, a digital 'scope or turn the brightness at max. > > > > On Mon, Jul 23, 2012 at 6:31 PM, jmfranke <jmfra...@cox.net> wrote: > > > >> Do not be too quick to toss out the antennas. Some receivers need the > >> antenna power to be connected to a pin on the receiver connector that is > >> then internally routed to the antenna. > >> > >> John WA4WDL > >> > >> -------------------------------------------------- > >> From: "Stephen Farthing" <squir...@gmail.com> > >> Sent: Monday, July 23, 2012 12:11 PM > >> To: <time-nuts@febo.com> > >> Subject: [time-nuts] Trimble T Lassen 2 - > >> suitableantenna....advice.....questions > >> > >> > >> Hi Guys, > >>> > >>> I have a couple of Trimble T Lassen 2 boards I bought at a Hamfest - > >>> the guy told me they were left over from a contract he had and were > >>> brand new. He had a load and i bought a couple for use as a precision > >>> 1 PPS output for radio stuff. They were packed in static protection. > >>> When I apply power to both units I can hear the oscillator (12.504 > >>> MHz) on my comms RX. So I am assuming that they work. > >>> > >>> I bought what claims to be a Trimble compatible active antenna on > >>> EBay. I hooked it up to one of the boards and applied power, and put > >>> the scope on the one pps pin. However after 20 mins (which I assume is > >>> much longer than the unit requires to get a lock) I see no 1pps trace > >>> on the screen. :-( > >>> > >>> So my working assumption is that the antenna is not working. The > >>> antenna position is fine as my elderly Garmin GPS2 which must be 12 > >>> years old sees 6 satellites there. > >>> > >>> Can anyone recommend a suitable antenna? I have a number of DIY > >>> designs I can try (Patch, Turnstile) but the Trimble docs say it needs > >>> an active antenna so I guess I'll have to spend money :-( > >>> > >>> While i am on, can anyone suggest a reasonably priced unit that has a > >>> 1pps output, NMEA and a built in antenna. Because I want to use this > >>> with an 8 bit embedded system I am probably not going to be able to > >>> hack one of the many cheap USB dongle GPS's. > >>> > >>> Lastly, has anyone found a GPS that will work with an Ipad. What the > >>> man in the Apple shop failed to tell me was the non 3g model lacked > >>> the built in GPS :-( > >>> > >>> Thanks in advice.... > >>> > >>> Steve > >>> > >>> > >>> > >>> -- > >>> Wisdom demands a new orientation of science and technology towards the > >>> organic, the gentle, the non-violent, the elegant and beautiful. E. F. > >>> Schumacher > >>> > >>> _______________________________________________ > >>> 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. > >> > > _______________________________________________ > > 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. > > > > -- > > Chris Albertson > Redondo Beach, California > > _______________________________________________ > 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.