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

Robert Darlington rdarlington at gmail.com
Mon Aug 20 00:27:07 EDT 2012


It's a pain to capture on any scope, but really easy to see with an
LED across the output.  it's not bright, but definitely easy to see on
my tbolt.

-Bob

On Mon, Jul 23, 2012 at 10:11 AM, Stephen Farthing <squirrox at gmail.com> wrote:
> 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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