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

Stephen Farthing squirrox at gmail.com
Mon Jul 23 16:11:43 UTC 2012


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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