A receiving loop for longwave (by DF3LP)
One major problem receiving long waves (e.g. 137 kHz ham band) is the presence of local noise sources. Here in North Germany all faint amateur signals on 137 kHz are covered by a curtain of LORAN-C sidebands from the island of SYLT (120 km NW from this site).
So I decided to erect an antenna which is able to cancel out this unwanted source. One possible answer is to build a magnetic receiving loop. "Magnetic" means that it is only sensible to the magnetic field vector and provides two sharp nulls at the broad sides, rectangular to the plane of the loop. These nulls are almost independent to the mounting height of this antenna. The polarisation of a "standing" loop is vertical.