Network capability
The top speed of your connection will be limited by the maximum speed of the mobile phone company's network. In the UK, O2, Orange and T-Mobile support 1.8Mbps, Three support 2.4Mbps and Vodafone support speeds up to 7.2Mbps.
However, it's one thing for the network to theoretically support these internet flowers speeds, but if the link from the mobile phone company's mast back to the internet (called 'backhaul') isn't fast enough you won't be able to hit the higher speeds. This is similar to having a 54Mbps WiFi router at home, but connecting it to an 8Mbps ADSL connection streamyx main you speed is limited by the slowed link in the chain.
Modem capability
Mobile broadband modems come in a variety of different speeds - from basic 3.6Mbps devices through to the fastest 7.2Mbps with support for high speed uploads. If your phone company offers 7.2Mbps broadband, but you've only got a 3.6Mbps modem, you won't be able to hit the higher speeds.
Looking beyond just the speed of the modem, it's important to consider the technology inside the modem itself. Of particular importance is a technology called receive broadband anywhere - modems that support this feature have two internal aerials instead of one, making them a lot quicker, especially in poor coverage areas.
Signal strength
The speed of your connection is affected by the strength of the signal you receive from your mobile phone company's network. The poorer your signal strength, the slower your connection. The software included with your modem will show you what your signal strength is - this is similar to the bar indicator you have on your mobile phone.
If your in an area of poor or no 3G coverage, your modem will switch to use the much slower 2G network - instead of internet trading speeds of 1.8Mbps, speed up internet be crawling along at just 30Kbps. The modem software or the lights on the modem itself will tell you if you're cable dsl 3G or 2G.
You can improve your signal strength by moving your modem. Try moving closer to a window (as the signal can pass through glass more easily than walls), or try moving the small business broadband floor of your home or office. You might find a USB extension cable useful.
You may notice that the strength of your signal changes throughout the day - this is called the 'breathing' effect of 3G networks. As the network gets busier, the coverage area shrinks, therefore you'll see your signal strength reduce too.
Number of other users on the network
The speed of your connection will be reduced during busy periods on the mobile network. When you connect using mobile broadband, you're using a shared data service. This means although your data is secure, the 'pipe' that you're using is also used by other ssm malaysia on the network. As more people go online and start downloading using the same pipe, the speed each user receives reduces. It's similar to the difference between driving on motorway at 2am versus 6pm.
As odd as it sounds, the number of customers making voice calls will also have an impact on your speed. This is because voice customers take priority over data customers on the network and during busy times voice customers are allowed to access the network ahead of data customers.
In general, the busiest time to use mobile broadband is between 6pm and 11pm - during this you'll find your speed much slower than using it first thing in the morning.
Jasper works in the mobile industry and is an expert on mobile broadband. He regularly contributes to Mobile Broadband Rocks - a blog dedicated to mobile broadband.