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

Chris Albertson albertson.chris at gmail.com
Mon Jul 23 16:58:40 UTC 2012


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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