Vodafone's USB Modem Stick is a mobile internet adaptor, and its support for HSDPA gives it the edge over previous 3G adaptors, with a claimed top download speed of 7.2Mbps.

It seems you can't read a national newspaper, turn on the TV or walk passed a billboard without being bombarded with adverts for mobile internet services.

Operators promise 'broadband on the move', offering 3G adaptors enabling us to browse the web, send emails and download large files at high speed.

Vodafone's USB Modem Stick is the latest such device and its support for High Speed Downlink Packet Access (HSDPA) gives it the edge over previous 3G adaptors with a claimed top download speed of 7.2 megabits per second (Mbps).

This new model Vodafone USB Modem Stick is much smaller than Vodafone's Pebble 3G adaptor. It's about the same size as an early USB memory stick, but still wide enough to render the adjacent USB ports on some laptops unusable.

Fortunately Vodafone supplies a USB extender cable in the Vodafone USB Modem Stick's box.

But these are minor grievances - the Vodafone USB Modem Stick is a sleek device, with the small tray that houses the SIM card being the only design point of note. Plus, installation is a breeze – XP and Vista users will find that drivers install automatically, so they'll be connected in no time.

However, it's the download speeds that most people will be interested in.

Actual 3G speeds rarely match manufacturers' claims, and the Vodafone USB Modem Stick is no different.

In our central London office - which like much of capital is covered by Vodafone's HSDPA network - we generally achieved between 1.8Mbps and 2.2Mbps. In real terms, that allowed us to download a 56MB file in just five minutes.

On the outskirts of London and on the 40-minute train towards the South West, however, the Vodafone USB Modem Stick's internet access was flaky, frequently switching to GPRS and completely dropping out in some instances. Once we'd arrived at our destination, we were back on a standard 3G network.

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