Further complication arises when adjacent transmitters have to transmit on the same frequency and under these circumstances the broadcast radiation patterns are attenuated in the relevant direction(s). A good example of this is in the United Kingdom, where the Waltham transmitting station broadcasts at high power on the same frequencies as the Sandy Heath transmitting station's high power transmissions, with the two being only 50 miles apart. Thus Waltham's antenna array [http://www.aerialsandtv.com/walthamtx.html#WalthamsTransmittingArray] does not broadcast these two channels in the direction of Sandy Heath and vice versa.