tv aireal

we have a status 570 aireal on our motorhome which you push up when on site itv reception is good but bbc is sometimes very poor despite numerous trys to get a better signal. my question is if we open the wardrobe door whrre it is fitted we get good bbc tv anyone know why thanks for any advice

This seems to suggest that your Status 570 above your roof isn't working as it should, you get a better signal inside your van when the wardrobe door is open. Would I be right in thinking that your aerial booster amplifier is in your wardrobe, where it's able to pick up the BBC transmission better than from your roof aerial?

yes

Some aerials require a 12V supply because they aren't passive, I don't know about the Status 570, if so this would be additional to the amplifier box in the cupboard

If you had a simple portable aerial plug this straight into your TV, if that works then plug this aerial into your amplifier and see if that works the TV too. You might be able to narrow down if the roof aerial is faulty or there's no 12V supply being delivered to the Status 570. Without a specification sheet I'm just guessing. In any event you need the amplifier box to be powered on as shown by its LED.