Abstract: The large wavelength at high-frequency (HF) band imposes critical challenges in platform conformal HF antenna designs, especially when multiple HF antennas are required in multifunction ...

Abstract: Antennas operating at the high-frequency (HF) band (3–30 MHz) are often electrically small due to the large wavelength of electromagnetic waves (10–100 m). Passive electrically small ...

ABSTRACT: On 25 October 2013, the Sun emitted two significant solar flares. The first solar flare, classified X1.7, peaked at 08:01 UT. The second one, X2.1, peaked at 15:03 UT and was accompanied by ...

A century ago, when the International Amateur Radio Union was formally founded, this hobby looked very different than it does now. The whole world was different then, the human evolution has ...