TomTom Navigator 2 Bluetooth GPS

In-car satellite navigation is now well worth having if you can afford it. But therein lies the rub - to add it to your new car specification can cost £1,500 or more and only the more luxurious models offer it. Fortunately, this is an area where powerful PDAs are stepping in, although up until now the systems have been model-specific and primarily aimed at the ever-popular iPAQ. With the release of Socket's Bluetooth GPS Nav Kit and TomTom's Navigator 2 Bluetooth GPS, any Bluetooth-equipped PDA running Pocket PC 2002 will do, widening your options immensely.

It's when you start using these systems in earnest that the true value of the wireless link comes in. The transmissions from GPS satellites are very low power - around 50W - and anything much more than a pane of glass blocks the signal. Even athermic heat-reflecting windscreens, as fitted to many newer cars, will prevent the GPS from locking on. With the iPAQ Navigation System or Navman's products, it's a struggle to position a PDA with a GPS card so it picks up a signal but is still visible while driving. With the Socket or TomTom, you can put the GPS receiver itself under your windscreen and the PDA next to your other dashboard instrumentation. Both units have sockets for external aerials too.

As standard, Socket's GPS comes without any means of attachment. You don't get anything to mount your PDA on either, and it even lacks an AC adaptor, so you'll have to recharge its lithium ion battery using the DC car adaptor. Fortunately, the latter splits into two 5V cables, allowing you to power both your PDA and your GPS simultaneously. The only other accessory is a leather belt pouch for the receiver.

The TomTom comes with a bit more in the box. As well as the essential cigarette lighter adaptor, again split into two 5V supplies, you get an AC adaptor with international plug set, a permanent power lead, an iPAQ charger adaptor, plus a clip-in cradle. The base of the unit is magnetic, and a baseplate with strong adhesive is also supplied, allowing the TomTom to be easily secured in the car.

For testing, I used an iPAQ 3970 with built-in Bluetooth and added a 128MB Lexar SD memory card from Crucial (www.crucial.com/ uk) for map storage. Installing the Socket's MyNavigator software onto the PDA was painless. The manual gives ample information on bonding the GPS to the PDA via Bluetooth and configuring a serial connection, after which it worked flawlessly. The GPS info screen displays the raw data, which mainly helps confirm the GPS is talking to the PDA correctly. The connection was re-established quickly if either the PDA or GPS were turned off temporarily.

However, I tested MyNavigator's routing abilities around London and found that the maps could occasionally miss important road limitations. For example, one route tried to get me to turn right where a mid-road barrier prevented this from being possible. At least you're kept well informed of your current location - not only are you told what road you'll be turning into next, but also where you're passing currently, including house number ranges. Route recalculation seemed swift, and you can also choose quickest, shortest, major or local road routes, plus it's possible to ask for alternative routes to be calculated until you find one you like. The software has a comprehensive database of points of interest, including ATMs and petrol stations. You can set the routing to exclude toll roads and give you a speed alert - either fixed or automatically based on road type.