Sadly, it’s not always a case of punching a postcode into your satnav and arriving promptly at your destination. Our real-world test uncovered a few problems along the way. So here are our tips for drivers armed with a satnav device.

HOOK INTO SPEAKERS
The speaker on smartphones is weedy in comparison to those on dedicated satnavs, making it difficult to hear instructions on motorways, or if John Humphreys is terrorising a politician on Radio 4. If your car stereo has a 3.5mm input, connect this to your smartphone and pipe the instructions through your speakers. Alternatively, connect the phone to a Bluetooth speaker, such as the SuperTooth Buddy.
DON’T RELY ON POSTCODES
Postcode searches are fine in towns and cities, where a single code may cover only a handful of houses. They’re less reliable in rural areas, where one postcode can cover an entire village. Make sure you have a full address before setting off.
BEWARE HEATED SCREENS
Heat-reflective or heated windscreens can interfere with GPS reception, leaving your satnav starved of satellite signals. You may be able to address the problem by fitting an external antenna and running the wire up behind the rear-view mirror, where there’s usually a gap in the heated windscreen mesh.
AVOID UNIVERSAL CRADLES
Free satnav becomes decidedly more expensive if your smartphone leaps out of the cradle and smashes into your steering column. Universal cradles can be an accident waiting to happen, as they aren’t moulded to the exact contours of your phone and often rely on weak clamps to hold it in place.
STAY UP TO DATE
Roads, speed-camera positions and speed limits change all the time, so take advantage of any updates that come your way. TomTom offers free map updates for the first year of any device, for example, while fortnightly speed camera updates await CoPilot owners.
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