SHS Testing - TangoGPS, GPS Antenna - zero byte PNGs!

Philip Rhoades phil at pricom.com.au
Wed Nov 3 18:49:55 CET 2010


People,


On 2010-11-04 04:17, Philip Rhoades wrote:
> Mariusz, Nikolaus, Sebastian,
>
> Thanks for the fast responses!
>
> See inline responses:
>
>
> On 2010-11-04 03:27, Dr. H. Nikolaus Schaller wrote:
>>
>> Am 03.11.2010 um 17:08 schrieb Philip Rhoades:
>>
>>> People,
>>>
>>> I wanted to start using the GPS facilities on my FreeRunner but there is
>>> a Catch 22 situation:
>>>
>>> - If I am inside, there is too much concrete to get GPS signals
>>>
>>> - If I am outside, I don't have a connection to download maps
>>>
>>> I thought if I could get an external GPS antenna connected and lead it
>>> outside to my balcony, I could get GPS reception while I was still
>>> inside (it is not always convenient to go out to the balcony and use
>>> WiFi).  I assumed (!) the little antenna connection on the top right
>>> edge of the freerunner was for a GPS antenna but when I went to buy one
>>> the guy told me the connection is for a 3G antenna . . if I look at:
>>>
>>> http://wiki.openmoko.org/wiki/Neo_FreeRunner_GTA02_Hardware#GPS_Antenna_Performance
>>>
>>> it seems to suggest that there IS an external connector for GPS?
>>>
>>> Can someone clarify?
>>
>> The guy is definitively wrong. The Freerunner doesn't support 3G...
>>
>> There is a connector for an external GSM antenna just near one
>> of the two Torx screws. You can see it when you open the battery cover.
>>
>> The golden connector is a "MMCX" type and provides approx. 3V 15mA for
>> an external antenna.
>>
>> I am using a Navilock antenna similar to this one (sorry, it is in German):
>>
>> 	http://www.ddcom24.de/shop/artikel_artikel_8556_name_Navilock-GPS-Zusatzantenne-NL-70ATW-MMCX-90%B0-gewinkelt.html
>>
>> Please make sure you get a MMCX (and not a MCX) connector.
>
>
> Right.
>
>
>> For the GPS performance tests we do, I simply place the Freerunner
>> on a window board so that it looks upright and the upper part of
>> the Freerunner looks outside. You may have to use one or two
>> books (e.g. Shakespeare complete edition...).
>
>
> My balcony windows face more residential blocks - in the past I have had
> to go out on the balcony and put the FR near the railing to get anything . .
>
>
>> This is not optimal for satellite reception with the built-in antenna,
>> but much better than inside a room. With that setup you usually get a fix
>> within 2 minutes (sometimes it may take 15 minutes since the
>> receiver can only see less than half of the sky and there may not be
>> enough visible satllites).
>>
>> After getting a fix, the receiver is sensitive enough to track even inside
>> a room.
>
>
> I am hoping that I can get an antenna connection and connect it to a
> wire going outside?
>
>
>> Finally, you can download the important maps off-line onto a SD card.
>
>
> I now have 611 dirs and files under ~/Maps but I have tried all the zoom
> levels and tried dragging around on the screen but I can't get any
> pictures . .  Is there a way of (conveniently) setting my long and lat
> and then downloading so that I know the maps I am getting are from my area?


I have found out why I can't see any maps - they download but all the 
PNG files are zero bytes in size!?

Thanks,

Phil.
-- 
Philip Rhoades

GPO Box 3411
Sydney NSW	2001
Australia
E-mail:  phil at pricom.com.au



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