[time-nuts] anyone tried the cheap Lea-6T modules seen on eBay?

[SAIDJACK at aol.com]

Bert,
 
the LEA-6T actually has software bugs that show up in moving  applications 
and that need to be handled by the users' software, and they are  selling it 
for drone applications. Without any monitoring for these bugs the  units 
may really only be useful for stationary applications.
 
Why they would choose the 6T unit instead of a non-T unit at half the price 
 would only be because they got those as surplus really cheap I would  
think.
 
bye,
Said
 
 
In a message dated 11/25/2014 09:50:12 Pacific Standard Time,  
time-nuts at febo.com writes:

A Lea-6T  is only worth any extra money if you are using the sawtooth   
correction data coming out of it. With out correction a $ 14 unit is just  
as  
good.
Bert Kehren


In a message dated 11/25/2014  11:25:34 A.M. Eastern Standard Time,  
michael.cook at sfr.fr  writes:

You may  have seen them as   in
<http://www.ebay.fr/itm/Ublox-LEA-6T-GPS-Module-w-Compass-for-APM2-5-APM2-6-
Flight-Controller-Multirotor-/271641375221?pt=UK_ToysGames_RadioControlled_J
N&hash=item3f3f1671f5>
There   are other sellers with the same.
My idea was to see if one was suitable  as  a 1PPS locking source for my 
PRS10. The interest for me being  that it powers  directly from a USB 
connection 
and can be configured  with the Ublox’s u-center  software, so 
implementation is a no  brainer.
All I needed to do was to  replace the patch antenna with an  SMA-F 
connector and add a wire for the 1PPS.  Despite having less  than ideal 
antenna 
position, once the survey was complete  I was  getting +/-20ns jitter on 
the 1PPS 
which is within spec and stable  over  the day. 
However I was most disappointed to see that the 1PPS  output  voltage is 
only 2.16 +/-0.4V. According to spec it should be  Vcc+/-0.4V and I  have 
Vcc 
measuring 3.3V.  I can’t see the  board trace but the measured  voltage is 
the 
same on the PPS pad next  to the JST-SH connector and on the GPS  modules 
pin 
28 so it is not a  board issue. Unfortunately this is too low to  tickle 
the 
PRS10 1PPS  input. I guess I could add a buffer or AND gate to fix  it, but 
that  sort of defeats the object and introduces extra jitter and  offset.
It  is however enough for a Raspberry-Pi GPIO input, so I have  relegated 
it  
to NTP PPS. 

Has anyone out there got one of these and  seen  the same symptoms? Or 
maybe 
you have one and it is OK? I’d like to   know.

You will be able to see from the eBay photos that this a  6T-0-000  version 
which is an early version and it could be that they  are cheap as  some/all 
have this defect. So   beware.


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