850 MHz versus 900 MHz
 

Allow me to apologise if this problem has already been addressed in this forum - I was unable to find anything like this.

If I understand correctly, some cell phone networks use dual frequencies - for example 850 MHz/2100 MHz where the 2100 MHz is used in the built-up city areas and the 850 MHz would be for all other areas. Another frequency pairing is 900 MHz/2100 MHz.

My Blackberry came from Australia, from my company. I use it in New Zealand. The company would usually use the Blackberry on the Australian Optus network. It is a Blackberry 9700 Bold. In New Zealand, I am using a Telecom New Zealand SIM card to operate the phone.

I have a reception problem that I'm not sure whether it is due to the network or the handset. In some places, close to the city centre, there is no reception on my phone.

Telecom NZ think it might be because the Blackberry is trying to use 2100 MHZ/ 900 MHz but their network uses 2100 MHz / 850 MHz.

Vodafone in New Zealand use 2100 MHz / 900 MHz. And Optus in Australia used 2100/900 too.

If my Blackberry is truly unlocked, shouldn't it be able to use both of either of these frequency pairings? Shouldn't it work on either Telecom NZ or Vodafone NZ? If I understand correctly, it is a quad-band phone.

A failure to operate on either of these frequency pairings would limit the ability of the phone to roam right?

Re: 850 MHz versus 900 MHz
 

Hello again, I just read the FAQs and I have confirmed that my Blackberry is Unlocked.

Re: 850 MHz versus 900 MHz
 

No. It can only use the frequencies it has hardware for.
Also, when mentioning Quad Band this is always about GSM and not UMTS (3G).

Re: 850 MHz versus 900 MHz
 

Hi thanks for the reply. So, if I understand correctly, a Blackberry can ONLY operate on either 2100/900 MHz OR 2100/850 MHz? There are different models to achieve this?

Re: 850 MHz versus 900 MHz
 

Yes.
If it only has the hardware to connect to the UTMS frequency of 2100/850 then that's all it has.

Just like there are 2 9700 models, one for T-mobile US and one for AT&T, because they use different 3G frequencies.

Re: 850 MHz versus 900 MHz
 

Thanks very much for clarifying. Makes things interesting when it comes to international roaming! Thanks again.