Reception thru Static and Interference

The effects produced by static (strays) are considered, and the Eccles classification of static as grinders, clicks, and hisses is adopted. Previous attempts to eliminate strays are described with explanations of their non-operativeness. Researches are described which indicate that grinders, the predominantly objectionable summer static, act as if propagated vertically. A balanced antenna structure consisting in effect of two horizontal loops is used to eliminate grinders. Signals in the loops add in the secondary circuit in proportion to the separation of the loops relative to the wave length, while vertically propagated grinders in the loops balance out in the secondary. Clicks are found to be horizontally propagated strays, and a special three-antenna arrangement for practically eliminating them is described and explained. Experimental work at various stations using these arrangements is described, and the capabilities of the new systems indicated.