[time-nuts] New timing receivers?

mike cook michael.cook at sfr.fr
Tue May 6 11:03:37 EDT 2014


A couple of points I discovered while building these things.

 This morning I got an Adafruit Ultimate (MTK3999) and a uBlox neo-6M module. 
 The first thing I discovered after looking at the specs , was that both have on board LDO 3.3V regulators, so you can feed them 5V without harm. I had wanted to make up an interface board with usb power and a DB9 serial interface for them , but found that I already  had something that looked to fit the bill even though not the same size as these micro modules. I have some Trimble Resolution Ts and  SMTs for which I have bought PPS-Piggy interface boards from Partially Stapled, marketed by Tindie.com (disclaimer as usual). I think they have been mentioned here. These two little modules interface perfectly. You just have to re-map the socket when wiring up. It looks like just about any of the modern boards will do so, though you won't get all the chip pin outs . The only issue for me this morning was picking up the TIMEPULSE(1PPS) from the neo-6M. Ideally , to get a robust pin-out I would have drilled a hole next to the 4 supplied, put a via in and then a standard pin. I don't have the tools to do that and even then it might have been iffy as the hole would go through the ground plane, leading to possible isolation issues. So what I did, was to use one of the mounting holes which are isolated and lead the wire from there to the chip pin 3  over the back of the module and up through the central hole. Soldering that end wasn't easy. I first tried tacking it directly to the chip pad after I had scraped it a little to remove any varnish, though I don't think there is any, but for some reason I could not get a good join. So I scraped of a couple of mm of the pin3 trace down to the copper. I went really carefully as I suspect it is just a few  microns thick. Soldering the wire to the trace enabled me to get a good joint and both the 1PPS to pin and the LED work fine. 

I have photos: 
<http://stratum1.d2g.com/images/new-gps-modules/new-gps-modules%20001.jpg>
<http://stratum1.d2g.com/images/new-gps-modules/new-gps-modules%20001.jpg>

Le 29 avr. 2014 à 16:43, Attila Kinali a écrit :

> On Tue, 29 Apr 2014 08:02:06 -0400 (EDT)
> EWKehren at aol.com wrote:
> 
>> Looks like they are doing exactly what I suggested as one of the  
>> alternatives for saw tooth correction. They have a VCTCXO in the module, with  the 
>> computing power in their chip a no brainer. the question is how much will it  
>> cost and how important will it be for a GPSDO. Final cost at maximum 
>> accuracy is  what counts
> 
> Judging from their other parts, i would say resonable prices start
> from 20 pieces onwards.
> 
> 			Attila Kinali
> 
> -- 
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> the little doings of the day. I believe I could find something ridiculous
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> 			-- Sophie Scholl
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