Caution how you handle your Bluetooth GPS.

[Vic]

I have discovered a fundamental design weakness with the Leadtek 9357 Bluetooth GPS in that it can easily be destroyed by static electricity (a charge of only 300v which is nothing in static terms can destroy the first stage low noise amplifier). There are a number of alarming threads in these forums indicating that this is happening in quite large numbers across a range of units. I'm convinced that it is not only Leadtek devices that are susceptible to this as the component that is failing is a widely used device and a GPS patch antenna provedes a comparitively large surface for collecting static.

My original thread which tracks the discovery is here http://pocketgpsworld.com/modules.php?name=Forums&file=viewtopic&t=17472

I think my findings deserve a wider audience which is why I've posted here.

Vic

[lbendlin]

There were some rumours that a mobile phone close by could have fried the receiver but your explanations do make a tad more sense.
_________________
Lutz

Report Map Errors here:
TomTom/TeleAtlas NAVTEQ

[Vic]

Here is the bulletin from the manufacturer of the Low Noise Amplifier in the GPS http://www.infineon.com/cmc_upload/documents/011/1292/Appli086_010904.pdf

[Bodo]

Is there any way that this can be tested?
I mean, is there a way that a "safe" static charge can be sent to a GPS unit to check if it will fail?
The normal user of an GPS has no way of diagnosing a hardware problem in the way Vic has.
I suspect there may be a reasonably simple way to intrudoce a static discharge to it
If so, can something like this be added to reviews of new GPS devices?

[lbendlin]

You must be joking. This is one of the cases where the statement "Do NOT try this at home" has 150% validity.
_________________
Lutz

Report Map Errors here:
TomTom/TeleAtlas NAVTEQ

[Vic]

Static testing as such is impossible to do as it is completely destructive and unpredictable. The only thing you can do is prevent this destruction by using adequate protection in circuit design. It is clear by looking at my photo of the circuit of my BT GPS and the protection bulletin from Infineon that protection here is not adequate. This is bourne out by the posts on here describing the same failure.

I think another issue is possibly the case design of a unit as in the type of plastic compounds used in construction. Not being an expert in this fied but perhaps the type used in the Leadtek is not ESD 'safe' and as such allows a build up of 'dangerous' static charges which are easily collected by the flat surface of the antenna.

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