[time-nuts] UBLOX LEA-5T Programming?

Clint Jay cjaysharp at gmail.com
Fri Oct 9 10:16:35 EDT 2015


I am still learning and want to understand, if the PPS is good then why is
the programmable output bad, as I understand it thus far, the PPS is
derived from the same clock source or have I got that badly wrong?

On 9 October 2015 at 12:16, Bob Camp <kb8tq at n1k.org> wrote:

> Hi
>
> Doing a GPSDO by locking to the awful 10 MHz output from any of these GPS
> modules
> is not going to work very well. Given the very long time constants
> involved in a GPSDO
> control loop, doing it without code is going to be pretty difficult.
>
> A much easier approach:
>
> Grab the GPS PPS and a scope. Use it to set the Lucent boxes on frequency.
> Repeat the process
> once a week.  The direct lock will flop around by (likely many) ppb. Your
> manual set will probably keep it
> under 1 ppb for a week.
>
> Bob
>
> > On Oct 9, 2015, at 1:39 AM, Perry Sandeen via time-nuts <
> time-nuts at febo.com> wrote:
> >
> > Hi,
> > I have six of the older style (anodized solid aluminum case) Lucent
> crystal oscillators that I’d like to turn into simple 10 MHZ output
> GPSDO’s. I have some salvaged HP cases so I can have a linear PS and all
> other stuff in one package.
> > I’ve found two different choices of GPS relatively low cost units on
> Ebay.
> > One is a LUCENT M12+ GPS Timing Receiver W/100 Hz output  for  $19.99
> Item 171886538138.
> > The other is a UBLOX LEA-5T GPS module dev board 1PPS /USB/RS232/ntp ser
> with two 1 PPS outputs for $49.90. Item 251785217093.
> > IIRC, one output of a Ublox can be set to a 10 MHz.
> > Can this model be set to have a 10 MHz output and is it easily done from
> a PC? I have no coding ability.
> > For more money I’d get a simpler phase detector circuit, which is all
> I’m looking for. For less money I’d have to build more circuitry.
> > A factor I don’t know is if the ublox is that much better/newer to
> justify the price difference.
> > I already have packed away two Oncore units with either a 1 KHz or 10
> KHz output.
> > Suggestions welcomed.
> >  Regards,
> > Perrier
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-- 
Clint.

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