In most cases, blocking is caused by a reception problem - either the signal is too weak or there is some kind of interference. Talk to your retailer or alternatively we suggest you get in touch with the following organisations who can give you details of one or more members who operate in your area and guarantee their work:
A local installer will understand the circumstances and local geography in your area and suggest the best option available to you.
Please Note: We're unable to reply directly but look out for new FAQs here soon