[time-nuts] Trimble T Lassen 2 - suitableantenna....advice.....questions

[Bob Bownes]

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.chris at 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.boriani at 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 <jmfranke at 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" <squirrox at gmail.com>
> >> Sent: Monday, July 23, 2012 12:11 PM
> >> To: <time-nuts at 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
> >>>
> >>> _______________________________________________
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> >>>
> >>>
> >>
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>
> --
>
> Chris Albertson
> Redondo Beach, California
>
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