The only way to increase the range on a cordless phone is to improve the antenna system. Since the antenna is in the base, the easiest thing to do is move the base to a better location, as high as possible. If that is not possible, you can go to any radio repair shop and ask them to open the base and solder an external antenna connector to it. Mine was done for five dollars. Then buy an external high gain antenna of the correct frequency and place it as high as possible in an area free of obstructions. This will improve your range by between 10 and 50 percent. The simplest way is to Google long range phones and make sure you find one at 900 mhz which is a legal frequency. The other phones are illegal in North America because of their potential to interfere with frequencies on such bands as police and fire and amateur. Also, make sure it does not put out more than one watt, (still 10x the power of the average cordless phone). The Engenius is probably the best cordless phone which is legal in Canada and the US but it can get pretty expensive. There is no easy way to do it. I consider myself an expert because I have been researching the issue for many months. I recently bought an ATTCL82209. With the base in a good position with clear line of sight, mine gives me a range of 525 yards which is almost a third of a mile. With an external antenna I have obtained 800 metres which is half a mile. But an urban environment has so many obstacles and variations that consistent long range with any phone is impossible. There is a reason why so many people pay exhorbitant monthly fees to use a cellphone, cellphones are the only real solution to urban communication problems, and the cell providers know it. If you are in Canada, www.3centcell.com
, might be a viable solution. Trust me, I know my stuff, I have spent months researching every possible angle.