Receive Antennas & Receive Arrays — Technical Articles

The Receive Antennas & Arrays Knowledge Base explores dedicated RX designs for HF and contesting. From compact active loops to phased arrays like the EchoTriad, these articles cover design theory, null depth, RDF optimization, and noise rejection. All entries are datestamped to indicate their latest review or validation.

Receive Antennas — Technical Articles

• [2025-08-14] When Size Doesn’t Matter (Much): RX Antennas Below 1/12λ
• [2025-07-31] Understanding Current Taper in Receive Antennas
• [2025-07-17] Is a TX Antenna with High Radiation Resistance Always a Good RX Antenna?
• [2025-07-03] Is Radiating Resistance as Important for RX as for TX?
• [2025-06-19] Comparison of Our Active RX Antennas
• [2025-06-05] RX vs TX Antennas — A Fundamental Difference
• [2025-05-22] Why Short RX Antennas Are Nearly Immune to Nearby Objects
• [2025-05-08] Why You Still Need a High Dynamic Range Radio — Even with an Active Antenna
• [2025-04-23] Why Most RX Antennas Excel at DX Reception vs Multiband Wires & Verticals
• [2025-04-09] Safe Distance for Active Antennas from the Home
• [2025-03-26] Active RX & TX Antenna Proximity: Safe Distances & RF Protection
• [2025-03-12] Understanding the Null of a Shielded Active H-Field Loop
• [2025-02-26] Understanding Noise Figure (NF): When It Matters and When It Doesn’t
• [2025-02-10] Common-Mode Rejection (CMR) & CMRR — What They Really Mean
• [2025-01-27] Understanding IP3: What It Is and What It Isn’t
• [2025-01-13] The Wilkinson Divider — A Superior Choice for Splitting RX Antennas
• [2024-12-30] Why MMICs Behave as High Impedance Below Their Intended Range
• [2024-12-16] When Is a Rotator Useful on an Active Magnetic Loop?
• [2024-12-02] LoG with a 9:1 Transformer? Quiet but Inefficient
• [2024-11-18] Galvanic Isolation with a 1:1 UNUN on RX Mitigates Noise
• [2024-11-04] Why MMICs Beat Low-NF Op-Amps in Real-World RX Antennas
• [2024-10-21] Skin Effect in RX Antennas: Myths, Facts & Real Impact

OctaLoop

• [2025-07-14] Why an OctaLoop Beats Square or Circular Loops
• [2025-06-29] Height vs Performance: Optimizing the OctaLoop

VerticalVortex

• [2025-07-02] Mounting the VerticalVortex
• [2025-06-16] Why the VerticalVortex Excels at Low-Angle DX (But Not NVIS)
• [2025-05-31] Why the 6 m / 35 mm VerticalVortex eProbe Works for 160–80 m RX

PulseRoot

• [2025-06-23] PulseRoot vs Traditional Full-Length Beverage

Receive Arrays

• [2025-08-12] RX Arrays: Why MMIC-Based Phasing Beats Old School Wire Wound Systems
• [2025-08-10] Gain Isn’t Everything: The Quiet Superpower of RX Phased Arrays
• [2025-07-27] Geometric Mean: The Secret to Multiband RDF Balance
• [2025-07-12] The Destructive Null: When Directionality Bites Back
• [2025-06-26] Drop the Null: Why Modern RX Arrays Should Focus on RDF
• [2025-06-09] One Month of Phasing: What We Really Learned
• [2025-05-24] Why RX Arrays Often Beat Big Yagis in Contesting
• [2025-05-06] Clever Phasing: Smarter Receive Arrays for Every Band
• [2025-04-19] Clever Phasing with 4 Cardinal BoGs: 8 Directions, Minimal Tradeoff
• [2025-04-02] Unlocking NVIS with the PolarFlip — Why Circular Beats Linear
• [2025-03-17] Installing the EchoTriad Phased Array System
• [2025-03-01] EchoTriad RX Array Spacing Calculator (45° Hybrid)
• [2025-02-12] Why You Might Not Need NEC: Simple Models for RX Arrays
• [2025-01-26] Spatial Phasing — Why RF.Guru Uses Fixed Hybrids
• [2025-01-09] EchoTriad: 6–12 dB Better SNR Than a Yagi