US triband vs EU triband

[Joerg Reisenweber]

I just confirmed basic functionality of 850/1800/1900 devices (US Freerunner)
for 900MHz networks. RF sensitivity is poor, but sufficient for areas with
good coverage.
For Germany a US device (850/1800/1900) worked flawlessly with German operator
T-Kom (in urban area), and rather poor with Vodafone. Both are 900MHz
networks.

Please notice I didn't yet check for the actual band used, so *if* T-Kom *and*
Vodafone both had 1800MHz BTS here in the tested area, then this report might
be moot. Anyway the result meets expected behaviour and 1800MHz BTS are not
known for either operator.

cheers
jOERG


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[Dieter Spaar]

Hello Joerg,

Joerg Reisenweber wrote:

> I just confirmed basic functionality of 850/1800/1900 devices (US Freerunner)
> for 900MHz networks. RF sensitivity is poor, but sufficient for areas with
> good coverage.
> For Germany a US device (850/1800/1900) worked flawlessly with German operator
> T-Kom (in urban area), and rather poor with Vodafone. Both are 900MHz
> networks.
>
> Please notice I didn't yet check for the actual band used, so *if* T-Kom *and*
> Vodafone both had 1800MHz BTS here in the tested area, then this report might
> be moot. Anyway the result meets expected behaviour and 1800MHz BTS are not
> known for either operator.
>  

So this is what I suspected but could not be answered by anyone till now.
According to my investigation the only difference between the two
variants should be a different filter in the reception path, in one case a
bandpass filters GSM850, in the other it is GSM900. Transmitter path
should be the same. As a result the phones should work in all four bands,
however with about 30 dB less signal strength in the not supported band.
A different issue is calibration, its not sure if the transmitter path
for all
four bands is calibrated properly.

Best regards,
  Dieter

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