[time-nuts] GPS module recommendation for Pi timing

[jimlux]

On 3/13/20 8:17 AM, Brian Lloyd wrote:
> On Fri, Mar 13, 2020 at 9:59 AM Peter Membrey <peter at membrey.hk> wrote:
> 
>> Hi Brian,
>>
>> We published this back in 2016 but it provides an analysis on the
>> stability of the STC on the first three generations of Raspberry Pi as well
>> as the stability profile of the uBlox M8Q:
>>
>> https://crin.eng.uts.edu.au/~darryl/Publications/Pi-hat_current.pdf
> 
> 
> Thank you. Perfect. Reading now.
> 
> Bob KB8TQ: We are laying out our own board as it will be doing other things
> besides GPS time/frequency keeping. Trying to avoid the use of USB. 1pps
> will go directly to a GPIO pin, assuming that will provide the best
> performance.
> 
> Hal Murray: Yes, I am trying to discipline the system clock.
> 
> Arne: Yes, I was considering using gpsd.
> 
> Right now I am leaning toward the Ublox LEA-M8T. I have a use for the other
> programmable output from the Ublox.
> 
> 
I've been working on a similar project - using a battery powered 
beaglebone and a GPS with an RTL-SDR to build an interferometer.

I was able to get a NEO-7 hooked up, chrony installed and running, etc. 
on 4 nodes.
what I have not been able to do is figure out how to sync the RTL-SDR 
(or, at least, get a 1pps hack into the data stream) - I might just go 
to a fancier RF interface like a Lime mini.