Cordless phone leaks conversation over 440 mhz GMRS frequency.

This is not a "walkie talie" conversation. It is a cordless phone leaking onto a GMRS frequency.

What is the best cordless phone for a New York City Apartment ?

I know 5.8 GHZ is the best frequency to get. Is there anyone out there who lives in Manhattan, that has a cordless phone that works well when pretty far from the base ? I think that if the phone has an antenna that helps as well, not sure.