Hello Marcel,
On Wed, 08 Apr 2009 18:19:20 +0200, "Marcel Klein" marcel@koeln.ccc.de wrote:
Okay now I have access to some more cell phones. But still the same issue even with a Nokia 3330 and Nokia 6210.
Sony Ericson k800i (no branding) - doesn't find the network most of the time or rather takes very long (when I'm lucky). Only one network in list when it manages to find my network. (Just happened once that everything was correct).
Nokia 3330 and 6210 - Finds the network quick or just needs to be rebooted. Only one network in list.
Siemens S45 - Network not found (yet)
I already tried several networks that really exist but without success. ARFCN is free and stable - I checked this with a radio.
I am rather sure this is an issue with the BS-11 clock. It requires a very accurate and stable clock for GSM (in my tests with just one phone a BTS clock detuned by about 1 ppm causes the phone to no longer see both test network and official network). There are most certainly differences between the phones too in regards to how much inaccuracy they tolerate.
You can make a test to see if it is a problem with the clock: take a SIM card from a phone which is registered (location updated has been done) to the BS-11 network and put it in a phone which did not find the BS-11 network. Now the phone should be able to see the BS-11 network when powered on because it immediately listens on the ARFCN of the BS-11 and does not register (and synchronize its clock) to an official network first. However it most certainly will no longer find the official networks.
Best regards, Dieter
Dieter Spaar wrote:
I am rather sure this is an issue with the BS-11 clock. It requires a very accurate and stable clock for GSM (in my tests with just one phone a BTS clock detuned by about 1 ppm causes the phone to no longer see both test network and official network). There are most certainly differences between the phones too in regards to how much inaccuracy they tolerate.
You can make a test to see if it is a problem with the clock: take a SIM card from a phone which is registered (location updated has been done) to the BS-11 network and put it in a phone which did not find the BS-11 network. Now the phone should be able to see the BS-11 network when powered on because it immediately listens on the ARFCN of the BS-11 and does not register (and synchronize its clock) to an official network first. However it most certainly will no longer find the official networks.
Yep you are right. Tried that just now.
Hm wouldn't it be possible to sync our clock with the official networks (without an extra ISDN-line)? Somebody told me that there are several ways to sync the clock. Here we discussed the ISDN way, but somebody told me that it should also be possible to set the clock over GPS and/or other networks in our area.
kenny_
Marcel Klein wrote:
Hm wouldn't it be possible to sync our clock with the official networks (without an extra ISDN-line)? Somebody told me that there are several ways to sync the clock. Here we discussed the ISDN way, but somebody told me that it should also be possible to set the clock over GPS and/or other networks in our area.
Or can't we just use ntpd? :D
(I'm already running my e1 card in slave mode...)
kenny_
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Dieter Spaar -
Marcel Klein