Gsm 850 In A Gsm 900 Country

Stu · 01-10-2006, 13:22

I'm in Dubai. I unlocked a friends Nokia 6103 today. The phone was a standard T-Mobile USA phone. I suspected the phone did not have GSM 900 but my friends was in the "oh yes it did mode."

To my amazement, the phone works ever so slightly. It doesn't work far more than it does. Every now and then, however, it is registers. I got a Welcome to the "UAE message" on the phone. If I leave it sit long enough, it manages to register.

Could you use this device as a communication device. No way. Is it working more than it should -- yes. I'm shocked and amazed.

Stu

VladS · 01-10-2006, 15:08

Quote:

Originally Posted by Stu

I'm in Dubai. I unlocked a friends Nokia 6103 today. The phone was a standard T-Mobile USA phone. I suspected the phone did not have GSM 900 but my friends was in the "oh yes it did mode."

To my amazement, the phone works ever so slightly. It doesn't work far more than it does. Every now and then, however, it is registers. I got a Welcome to the "UAE message" on the phone. If I leave it sit long enough, it manages to register.

Could you use this device as a communication device. No way. Is it working more than it should -- yes. I'm shocked and amazed.

Stu

If I'm not mistaken there are some channel overlaps between GSM850 and eGSM900.

**andy** · 01-10-2006, 15:17

I don't know the exact frequency bands; maybe there is some overlap at the edges, or the tuning is just tweaked sideways a bit. I'd be surprised though, as I imagine the band allocations are in the range of a few MHz or so, rather than 50 or more. Are there two offset duplex bands, like ordinary radio with repeaters?

GSM-Fan · 14-01-2007, 16:24

The phone has also GSM1800. So all you need is a 900/1800 network with not every station having 1800 to have the phone work "sometimes".

Stu · 14-01-2007, 18:18

To the best of my knowledge, the UAE is 900mhz only. We have a 2100mhz 3g network. In March, a competitor opens who is partially on the 1800mhz band, but this signal was not from the competitor, it was from the incumbent provider.

PhotoJim · 14-01-2007, 19:51

Quote:

Originally Posted by Stu

To the best of my knowledge, the UAE is 900mhz only. We have a 2100mhz 3g network. In March, a competitor opens who is partially on the 1800mhz band, but this signal was not from the competitor, it was from the incumbent provider.

The control channels are in different places on GSM 850 and 900, so even though there is some frequency overlap, it doesn't matter. The phone looks in the wrong place for control information and sees nothing.

You must be getting some GSM 1800 service (perhaps from further away if it's intermittent), or you're getting GSM 850 somehow.

Stu · 15-01-2007, 05:03

The phone, however, is programmed to do 850mhz or 900mhz just by changing one bite in the firmware. Isn't it possible that there was a minor glitch in the firmware of the phone that caused this to happen?

The experience made no sense to me. Who knows, may be the phone company does some picocells on the 1800mhz band and some nearby bulding had one. I never heard of Etisilat on the 1800mhz frequency, but they probably could could get TRA approval to transmit there in five minutes. The UAE cannot use that frequency for other purposes neighboring countries do have networks on that frequency and it would be a nightmare if the UAE opened it up for something else.

There is a sports stadium about a mile away. That's all I can think of.

Stu

GSM-Fan · 15-01-2007, 07:12

Something like a stadium is a pretty good guess for a small cell on 1800 MHz. But it's also possible that the signal comes from a regular sized station pretty far away because its signal is very clear due to the very low interference level.

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	(#1 (permalink))
Stu (Offline) Senior Member Prepaid Specialist Posts: 886 Join Date: 11 Feb 2004 Location: Dubai (& Detroit) Country:	01-10-2006, 13:22 I'm in Dubai. I unlocked a friends Nokia 6103 today. The phone was a standard T-Mobile USA phone. I suspected the phone did not have GSM 900 but my friends was in the "oh yes it did mode." To my amazement, the phone works ever so slightly. It doesn't work far more than it does. Every now and then, however, it is registers. I got a Welcome to the "UAE message" on the phone. If I leave it sit long enough, it manages to register. Could you use this device as a communication device. No way. Is it working more than it should -- yes. I'm shocked and amazed. Stu

	(#3 (permalink))
andy (Offline) Moderator Prepaid President Posts: 1,964 Join Date: 10 Dec 2004 Country:	01-10-2006, 15:17 I don't know the exact frequency bands; maybe there is some overlap at the edges, or the tuning is just tweaked sideways a bit. I'd be surprised though, as I imagine the band allocations are in the range of a few MHz or so, rather than 50 or more. Are there two offset duplex bands, like ordinary radio with repeaters?

	(#4 (permalink))
GSM-Fan (Offline) Junior Member Amateur Member Posts: 10 Join Date: 11 Jan 2007 Country:	14-01-2007, 16:24 The phone has also GSM1800. So all you need is a 900/1800 network with not every station having 1800 to have the phone work "sometimes".

	(#5 (permalink))
Stu (Offline) Senior Member Prepaid Specialist Posts: 886 Join Date: 11 Feb 2004 Location: Dubai (& Detroit) Country:	14-01-2007, 18:18 To the best of my knowledge, the UAE is 900mhz only. We have a 2100mhz 3g network. In March, a competitor opens who is partially on the 1800mhz band, but this signal was not from the competitor, it was from the incumbent provider.

	(#7 (permalink))
Stu (Offline) Senior Member Prepaid Specialist Posts: 886 Join Date: 11 Feb 2004 Location: Dubai (& Detroit) Country:	15-01-2007, 05:03 The phone, however, is programmed to do 850mhz or 900mhz just by changing one bite in the firmware. Isn't it possible that there was a minor glitch in the firmware of the phone that caused this to happen? The experience made no sense to me. Who knows, may be the phone company does some picocells on the 1800mhz band and some nearby bulding had one. I never heard of Etisilat on the 1800mhz frequency, but they probably could could get TRA approval to transmit there in five minutes. The UAE cannot use that frequency for other purposes neighboring countries do have networks on that frequency and it would be a nightmare if the UAE opened it up for something else. There is a sports stadium about a mile away. That's all I can think of. Stu

	(#8 (permalink))
GSM-Fan (Offline) Junior Member Amateur Member Posts: 10 Join Date: 11 Jan 2007 Country:	15-01-2007, 07:12 Something like a stadium is a pretty good guess for a small cell on 1800 MHz. But it's also possible that the signal comes from a regular sized station pretty far away because its signal is very clear due to the very low interference level.