MW radios usually have antenna coil wound over a ferrite rod. This makes the radio directional and one has to adjust the position of the radio by rotating it to receive maximum signal. Since MW stations come from all directions, it is easy to miss or receive poor signal if the radio is placed in a particular position.
Crossed Loop Antenna (CLA) solves this problem effectively. Unlike single loop conventional antenna, CLA has two antenna coils. These two coils are placed at right angle to each other. Each coil has half the inductance value required to cover the MW band. For example, if for a single loop antenna, the inductance value of the coil required is 310uH, for CLA, each coil is of 310uH / 2 = 155uH value.
By keeping the antenna coils at right angle, the reception of signals from various directions is greatly improved and no deep sharp nulls are observed. Back ground noise is also reduced considerably.
Please note that the received signal strength readings are only approximate. These have been obtained using cell phone based audio signal meter application, inside my workshop room, on actual radio stations. There may be significant reflections / attenuation inside the room, but these observations certainly indicate the marked improvement over single loop antenna.
Operating procedure:
MW Radio is placed on the CLA platform. Antenna is tuned with the help of VC1 at the desired frequency of station. The incoming signal will peak, irrespective of the direction of radio station, to give you a marked improved signal !
