The digital switchover is well underway in the London TV region.

A special event at Crystal palace tonight will mark the switching off of the old analogue signal, replaced by new digital airwaves for TV.

Nearly all sets can be converted to receive digital TV with a Freeview box, but is your aerial up to the challenge?

We've teamed up with One For All to give you the chance to win one of five state-of-the-art aerials to ensure the switchover is no problem for you.

One in ten analogue users may need to replace or adjust their aerial before they can join the digital revolution, according to One For All, the UK market leaders in TV aerials.

Rooftop aerials over ten years old may have corroded, especially in seaside locations, or they may be pointing in the wrong direction.

With a weak analogue signal you just get progressively worse reception, whereas with digital it may mean you simply can't watch TV at all.

Aerials will also need to be 'wideband' to pick up all services - otherwise you may find you can't receive channels such as C5 and ITV2, as well as new TV and digital radio channels added in the future. You may only get around 15 channels after the switchover, whereas there are more than 40 channels available.

Even homes with cable or satellite still have second or third TV sets in kitchens and bedrooms that receive their signal via an aerial - which may now need upgrading.

If there's no accessible TV point for an external antenna, or you're not getting all 40 digital channels, then a high-powered internal aerial is the solution – and we have five to give away in our great competition!

The One For All SV9365 amplified indoor antenna gives perfect reception of digital TV and DAB radio. It has an adjustable amplifier to boost signal gain up to 46dB and 'Signal Clear Technology' means only your picture quality is boosted, not the interference – thanks to triple noise reduction filters.

Easy to install, it can be powered via your set-top box or plugged into the mains.

It's suitable for most locations up to 15 miles from the transmitter. Check the type you need by visiting the aerial selector at www.oneforall.com/aerials

All you need to do to be in with a chance of winning an aerial is answer this simple question:

Which south London transmitter is marking the switchover with a spectacular light show?

Click here to email your answer, along with your name, address and a daytime contact number.

Competition closes at midnight on Monday, April 23.

Usual Newsquest terms and conditions apply.

If you're not lucky enough to win, One For All indoor and rooftop aerials are stocked by Argos, Dixons, Currys, PC World, Amazon, Comet and Sainsburys. The SV9365 aerial is priced £34.99.