[Gta04-owner] Status GTA04 GroupTour

Dr. H. Nikolaus Schaller hns at goldelico.com
Fri Dec 30 15:08:57 CET 2011

> Which leads us to the persitent problem of producing new cases (or adapters
> for existing cases). Maybe we can break the problem in two and try to find kits 
> for the missing components (antenna, etc.) on one hand and desigining a 3D 

For these parts I have some components sitting on my office desk waiting
to be evaluated next year ;). Those are some speakers bought from Mouser
and I expect that they don't make bigger problems.

A minor problem is to find a good source for vibracall motors. Mouser has one
in their catalog, but they are sold out for a long time and it appears they are EOL.

If someone knows a catalog distributor for such motors, please let us know.

The most complex "missing" part is the UMTS antenne. This needs a very careful design
so that we do not reduce the reception quality (remember the iPhone 4 issues?).

And even worse: if reception is bad, the transmitter has to increase the power
which draws the battery empty even faster. So a badly designed antenna has
dramatic effects on the overall performance.

Fortunately, we have a good RF engineer in our team, but as usual with volunteers
development takes a little more time as expected.

Technically the idea is to make the antenna as a flexible PCB so we can easily
add stubs or change trace widths and lengths at very low experimental cost
(e.g. 20-30 EUR for each protoype). Only the measurement tools cost >5000 EUR...

This antenna can be bent and stowed into a small slot of the case.

And finally, we may need a replacement battery in the future. But we can either
use the Nokia BL05 or similar or find another one or it should not be too difficult
to get a compatible battery through Alibaba.

Looks as if we have many more ideas in this community than can be completed
within Xmas- and New Year's holidays :)


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