FOCAL LINE MODIFICATION OF THE E/W ARM OF THE NORTHERN CROSS RADIOTELESCOPE The modification consisted in removing the entire focal line from sector 3 of the 1W channel of the E/W arm. The line was replaced with an array of 18 log periodic antennas that carry the signal, via coaxial cables, to waterproof boxes. Each box contains two front-ends, two optical transmitters, one micro-controller and one power supply since it receives the signals coming from two logs. Also in this case a canalization structure was built to carry optical fibers and power supply wiring to the data acquisition system. Log periodic antenna Receiver box Micro controller Power pack TX Optical F.E. Optical fibers collecting tray