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Phased arrays of short vertical antennas. A technical notes from Butternut antennas on phased vertical arrays

K4TR Manufacture and sell simple dipoles, half square 2 wire phased vertical arrays, end fed zepp antennas, G5RV antennas. 1:1 baluns

Optimizing weak signal reception on the HF bands, particularly in the presence of strong local QRM, often necessitates specialized receiving antenna systems. This resource details the _HI-Z Antennas_ product line, focusing on phased vertical arrays designed for superior noise rejection and directivity. It covers components such as the 4-Square and 8-Element array controllers, which allow for rapid switching of receive patterns, and dedicated low-noise preamplifiers to improve system sensitivity. The site also presents various bandpass filters, crucial for mitigating out-of-band interference and enhancing the dynamic range of the receiver. The HI-Z systems are engineered to provide significant front-to-back and side rejection, often yielding **20-30 dB** of attenuation to unwanted signals, which is critical for DXing and contesting. Users can achieve a notable reduction in local noise, allowing for the discernment of signals that would otherwise be buried. The array controllers facilitate quick pattern changes, enabling operators to null out interference or peak weak signals from distant stations, effectively extending the reach of their receive capabilities by improving the signal-to-noise ratio.

Wideband receiving phased arrays with small electric or magnetic active wideband elements are discussed in details. Practical results and examples are given.

Manufacturer of amplifier for small magnetic and electric receiving wideband antennas, and variable delay line kit for active antenna phased arrays

This article details the design and construction of a homebrew two-element loop antenna array for HF reception. The DIY receiving antenna system consists of two 30-inch diamond-shaped loops spaced 20 feet apart, offering superior directivity compared to traditional vertical arrays. The design features broadband operation from 160m to 20m bands, requiring only phase-delay adjustments via feedline lengths. This home-built antenna system achieves 9dB RDF (Receiving Directivity Factor) performance comparable to a 300-foot Beverage antenna, while requiring minimal space and no ground radials, making it ideal for suburban installations and low-band reception.

Operating within the low-frequency spectrum, transformers serve critical roles in antenna systems, particularly for 160m applications. The resource details the construction and performance of 1:1 transformers built on BN-73-202 cores, emphasizing their use as hybrid combiners or phase inverters for RX antenna arrays. Measurements reveal that these transformers exhibit minimal losses, around 0.12 dB at 1.8 MHz, with variations based on wire type and number of turns. The analysis includes comparative data on transformer performance, highlighting the impact of different winding techniques on frequency response. Notably, the use of coaxial cable for winding improves bandwidth while maintaining low-frequency efficiency. The resource also discusses braid breaker transformers, which minimize inter-winding capacitance, achieving low losses around 0.21 dB at 1.8 MHz. These insights are crucial for optimizing low-band antenna systems, allowing operators to make informed decisions regarding transformer design and implementation.

Phased array antennas are composed of multiple individual antenna elements that can have their phase and amplitude controlled to steer the main beam direction in real-time. They are used in radar, communications, and electronic warfare, and offer improved gain and reduced side lobes. A comprehensive document on Phased Arrays include techniques to increase the Antenna Gain and change the Radiation Pattern