gta02-core and external GPS antenna
steve at openmoko.com
Fri May 29 17:18:07 CEST 2009
Personally I always thought that a phone targeted at developers out to
many ins and outs as practicable. That said, On the sales side we never
much uptake for the external GPS antenna. From a logistics point of view
getting uniques off the board is a good good thing. I would concur with
to remove it. However, u may want to check with Tully on the mechanical
I have his personal email here somewhere in case he doesnt answer the om
Question: are you considering folding in the A8 changes? and the 1024 fix?
beware on the A8 microphone as it requires an annoying case mod. doable,
Werner Almesberger wrote:
> There's one simplification that looks attractive to make in gta02-core
> and that's to remove the external GPS antenna connector. From what I've
> heard, this antenna is rarely used in the FreeRunner, and for
> stationary use, one could connect an external antenna to the socket for
> the internal antenna.
> There are the following benefits in removing the external antenna:
> - reduced SMT cost by removing about a dozen components, some of them
> unique. Due to its shape, The antenna connector may also need
> special treatment in SMT, such as glueing.
> - fewer components means less risk of getting interferences. This goes
> particularly for the external antenna socket when open.
> - simplifies the layout of the GPS RF circuit and thus reduces the
> risk of us getting something wrong.
> - when investigating the SD/MMC vs. GPS problem, Andy found that the
> antenna selection circuit is operating with an incorrect voltage.
> Apparently, this didn't cause any observable problems, but then
> you never know what's really behind the occasional glitch ...
> - in case future designs are made based on gta02-core, a smaller GPS
> subsystem may allow for a smaller PCB size or give more room to
> other subsystems
> There are also a few disadvantages:
> - if you really need the external GPS antenna along with the internal
> one, this will not be a welcome change
> - the antenna connector also helps to hold the PCB in place. Without
> it, there is only USB on that side of the board to assist the
> snap-in mechanism. (Probably doesn't matter all that much, though.)
> - removing the connector leaves an empty hole in the case
> I think the benefits outweigh the disadvantages, so I'd like to see
> the external GPS connector gone.
> Any thoughts ?
> - Werner
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