Newsgroups: sci.electronics.misc,sci.electronics.equipment,sci.electronics.components,sci.electronics.basics,sci.electronics.repair
Subject: Re: Where to purchase portable cellular jamming devices - (no legal opinions please)
References:  <[email protected]>  
"Bob Shuman"  writes:

> And you would be basically correct.  In the US, these are generally referred
> to as cellular (850Mhz) and PCS (1.9Ghz).  The other standard cellular
> frequency that has opened up in some parts of the word is 450Mhz.

And agt some countries that 450 MHz frequency band has been used 
for cellular phone systems for decades! 
For example NMT (Nordic Mobile Telephone) network opened in Finland 
at 1982. That network was international standard covering many 
Northern European countries (at least Finland, Sweden and Norway). 
Later that system was expaded to be used als on Russia and 
many Eastern European countries. 

In Finland 450 MHz band became popular and pretty heavuly loaded. 
The new network based on same basic technology but perating at 900 MHz 
was started at 1987. 

This NMT system was an analogue system that is nowadays phased out, 
not operating in Finland anymore. 

The 900 Mhz frequency band is nowdays used by digital GSM cellular 
phone system. The use of GSM system started at 1992 in Finland. 
First it operated side by side at different channels at 900 Mhz 
frequency band. Later when 900 MHz NMT system phased out, 
the cellular phone band was entirely used by GSM system.

To get more capacity operators started around 1996-1997 to 
implement GSM network tat operates at 1800 MHz frequency band 
to ajor cities. The 1800 MHz network is generally used with 
"dual band" phones that can use both 900 MHz and 1800 MHz bands. 
The major operators in Finland have network operating at both 
frequencies, and the phones seamlessly switch between 
those networks automatically (user does not worry 
about frequency band). 

Most information on this posting is taken from my 
course paper I made at 1996 in Helsinki University of Technology. 
The paper is written in Finnish and available on-line at 
http://users.tkk.fi/~then/matkapuhelin/index.html
 
> Some cordless phones operate at the unlicensed 2.4Ghz, among other
> unlicensed frequency ranges as well.
> 
>  Bob
> 
> "WW"  wrote in message
> news:[email protected]...
> > In sci.electronics.components [email protected] wrote:
> > > Cellphones are damhard to jam, because they look for an open channel
> > > you have to interfere with the entire 2.4G band, and some others.
> > >
> > Cellphones use the 2.4GHz band? I always thought it was 900Mhz and 1800MHz
> >
> > -- 
> >
> > Wing.
> 
> 

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/