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

Bob Camp kb8tq at n1k.org
Fri Oct 9 07:16:10 EDT 2015


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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