Converting a small standard receiver into a hand-held narrow-aperture HF direction finder

Describes a compact HF-antenna accessory, designed for use with book-sized portable receivers. It converts the receiver for sky-wave-direction finding (DF), co-channel-interference reduction, and radio-frequency-interference (RFI) location, while being hand-carried by the user. When the system is operated in the DF mode while in motion, site-related errors in line of bearing (LOB) can be reduced by spatial averaging, and by over-sampling and excising "outliers." This approach is equivalent to increasing the effective aperture to improve resolution. Spatially averaging the LOBs permits useful DF measurements to be made in locations, so cluttered by scattering from nearby objects, as to be unsuitable with standard DF equipment. The receiving system has been designed to be as insensitive as possible to local reflections (including those from the operator's body).<
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