[Open-hard-software-event] Fwd: [Gta04-owner] GPS fix? Fixed.

Dr. H. Nikolaus Schaller hns at goldelico.com
Mon Nov 28 07:52:02 CET 2011


Wie unten geschrieben:

wenn jemand ein GTA04A3-Board (Early Adopter) hat und
zum Workshop mitbringt, kann der GPS-Antennenschalter
getauscht werden.

Grüße
Nikolaus


Anfang der weitergeleiteten E-Mail:

> Von: "Dr. H. Nikolaus Schaller" <hns at goldelico.com>
> Datum: 26. November 2011 11:39:04 MEZ
> An: List for communicating with real GTA04 owners <gta04-owner at goldelico.com>
> Betreff: Re: [Gta04-owner] GPS fix? Fixed.
> Antwort an: List for communicating with real GTA04 owners <gta04-owner at goldelico.com>
> 
>> 
>> Or we use
>> a replacement chip that appears to have the switch control signal
>> inverted. Christoph just has found one and we are evaluating if
>> it is indeed 100% compatible in all other parameters.
>> 
>> So you don't have to care about this GPS discussion...
> 
> Dear all,
> we have now replaced the antenna switch chip on three units
> and tested them. The internal antenna appears to work much
> better with this chip than with crossing over the wires.
> 
> So for the coming GTA04A4 boards, we will simply install the
> replacement during production.
> 
> Now, some of you have an early adopter board (GTA04A3)
> where GPS can't work.
> 
> My proposal:
> 
> * if you want to do it yourself (description below), and can't
> easily get the chip, please let me know and I can send you
> the chip in a letter envelope.
> 
> * or you can send the device to me and we will have it fixed.
> 
> * or if you plan to attend the OHSW.de workshop next weekend
> in Munich, please bring your GTA04A3 with you. Christoph will
> volunteer to replace the chips.
> 
> BR,
> Nikolaus
> 
> 
> Description
> ---------------
> 
> Due to a mistake done when copying the schematics of
> the GTA02 to the GTA04 design, the antenna inputs for
> the external and internal antennas got crossed over for
> the antenna switch chip (uPG2012TB).
> 
> Solution: replace the uPG2012TB with a uPG2010TB
> 
> The UPG2010TB is slightly different in its parameters, but
> has exactly the same pin layout. And - happily - an
> inverted truth table. I.e. the same control signal level
> throws the switch into the opposite position when compared
> to the UPG2012TB.
> 
> Replacement: get some uPG2010TB chip
> e.g. @DigiKey: http://search.digikey.com/de/de/products/UPG2010TB-A
> 
> Remove the uPG2012TB (marked G3A). This requires
> SMD removal equipment. A normal soldering iron is
> not sufficient! Please be very careful not to damage the
> copper pads and traces. And beware that you have to put
> a lot of heat into the PCB since it has 8 copper planes
> under the chip. This is much more than usual with
> single or two-layer PCBs.
> 
> Solder the uPG2010TB (marked G2Y) in the correct
> orientation. The correct orientation is if you can read
> the "G2Y" unrotated and the internal antenna is to the
> left, the Wi2Wi GPS receiver on the bottom (marking
> in same orientation) and the external MMCX socket to
> the right.
> 
> Test: you should now see 4-8 satellites within <1 minute
> after cold start with external antenna outdoors under
> open sky. Unplugging the external antenna and switching
> to the internal antenna should still show at least 3-4 satellites.
> 
> _______________________________________________
> Gta04-owner mailing list
> Gta04-owner at goldelico.com
> http://lists.goldelico.com/mailman/listinfo/gta04-owner



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