Baluns and Ununs — Technical Articles

The Baluns, Ununs, Chokes & Ferrite Knowledge Base is where we unpack the heart of impedance matching, isolation, and noise suppression. From Guanella vs Ruthroff designs to proper ferrite selection, these articles explain how transformers and chokes really work, where to place them, and which myths to ignore. Each entry is datestamped to indicate its latest update or validation.

• [2025-08-09] The History of RF Transformers
• [2025-07-25] A Brief Overview of BALUN Types and Their Applications
• [2025-07-11] A Brief Overview of UNUN Types and Their Applications
• [2025-06-28] The Guanella Transformer (Current Balun/UNUN) Explained
• [2025-06-12] The Ruthroff Transformer (Voltage Balun/UNUN) Explained
• [2025-05-29] The Autotransformer (Voltage UNUN) Explained
• [2025-05-15] The Hybrid Transformer Explained
• [2025-05-01] Autotransformer vs. Ruthroff Transformer in UNUNs and BALUNs
• [2025-04-20] Don’t Make This Mistake: Why RG402 is the Worst Choice for Common Mode Chokes
• [2025-04-05] Understanding Ferrite Coupling Efficiency Across Coaxial Cable Shield Types
• [2025-03-22] Why Measuring Your Coax Shield with a VNA Still Doesn’t Prove Your Choke Works
• [2025-03-07] Debunking Myths in Common-Mode Choke Measurements with a VNA
• [2025-02-18] Proper Grounding & Choking to Eliminate Common Mode Noise
• [2025-02-02] The Dual Roles of a 1:1 UNUN vs Line Isolator or Choke
• [2025-01-16] Unlocking Wideband Phasing with Modern Ferrite Materials
• [2025-01-02] Why Open Wire Is More Efficient Than a 4:1 Balun When Using a Tuner
• [2024-12-14] Balun, UNUN, and Line Isolator — Different Names, Same Core Function?
• [2024-11-29] Optimal Placement of Common-Mode Chokes for Various Antenna Types
• [2024-11-13] Bifilar vs. Coax: Which Winding Is Best for Chokes?
• [2024-10-28] Ampère's Law in Toroids
• [2024-10-12] RX Chokes: Why You’re Still Thinking Like a Transmitter
• [2024-09-25] Why Shielding Balanced Feedlines for HF Ham Radio Is a Bad Idea
• [2024-09-09] Why a 1:1 Balun Makes an Asymmetric Tuner Perform Like a Symmetric One
• [2024-08-21] Sleeved and Clip-On Ferrites Are Not for QRO
• [2024-08-05] Why Your Ferrite Might Be Cooking Alive