Welcome Back to the RF.Guru Incredible Lab Mailing

Dear RF explorer,

Whether you're chasing decibels, eliminating QRM, or diving deep into the physics of RF, this is your dispatch from the frontlines of signal clarity.

At RF.Guru, we don't just design antennas—we question assumptions, stress-test solutions, and share what we uncover. This newsletter is your access to the practical insights and field-tested engineering that shape our products and thinking.

Here’s what’s new in the lab—and what might just shift how you approach your own station:

• The Dual Roles of a 1:1 UNUN Choke vs Line Isolator
  Understanding skin effect and common-mode noise is key to clean RF. This article demystifies two often-confused phenomena: return currents from antenna imbalance versus environmentally induced common-mode pickup. It explains why both need different mitigation strategies, and how a properly placed 1:1 choke or line isolator can tackle each effectively.
  https://shop.rf.guru/pages/the-dual-roles-of-a-1-1-unun-choke-vs-line-isolator

• Currents on the Coaxial Cable – A Multi-Lane Highway of RF Behavior
  Your coaxial cable isn’t just a tube for signal—it’s a three-lane system with RF currents flowing in distinct regions: center conductor, inner braid, and outer braid. This article breaks down differential mode, shield current, and skin effect in practical terms, revealing how current separation impacts noise, efficiency, and radiation.
  https://shop.rf.guru/pages/currents-on-the-coaxial-cable-a-multi-lane-highway-of-rf-behavior

• Unlocking Wideband Phasing in Amateur Radio with Modern Ferrite Materials
  Wideband phasing networks are no longer confined to coax delay lines. This article explains how modern ferrite materials like nanocrystalline and amorphous cores enable compact, high-precision hybrids with stable performance across broad HF ranges. Ideal for phased arrays and diversity reception systems, these materials open the door to cleaner, simpler designs without sacrificing phase integrity.
  https://shop.rf.guru/pages/unlocking-wideband-phasing-in-amateur-radio-with-modern-ferrite-materials

• Trapped in a Trap – Coaxial Traps in Multiband Antennas
  Coaxial traps can make antennas resonate on multiple bands, but not without cost. This article explains why coaxial traps often introduce losses, tuning complications, and poor efficiency when stacked. It explores smarter alternatives, like mean-frequency methods, and offers a clear rule of thumb: avoid traps when you can, use one when you must—and always design for efficiency first.
  https://shop.rf.guru/pages/trapped-in-a-trap-coaxial-traps-in-multiband-antennas

• Coiled Into Compromise – The Truth About Loading Coils in Shortened End-Fed Antennas
  Loading coils may make an EFHW fit into small spaces, but they compromise where it matters. This article unpacks the efficiency drop, narrowed bandwidth, and poor current distribution caused by mid-wire inductors. Rather than blindly chasing resonance, it encourages smarter tradeoffs—and explains when a shorter wire simply isn’t worth the cost.
  https://shop.rf.guru/pages/coiled-into-compromise-the-truth-about-loading-coils-in-shortened-end-fed-antennas

• Why Clever Antenna Trickery Doesn’t Always Pay Off – A Real-World Test
  On paper, a loaded or folded multiband vertical might seem clever—but real-world results tell a different story. This article compares a “tricked” multiband vertical to a straightforward one with quarter-wave elements. Despite a perfect match, the clever design underperformed in every direction. It’s a reminder that low SWR isn’t everything, and that simplicity often wins in the field.
  https://shop.rf.guru/pages/why-clever-antenna-trickery-doesnt-always-pay-off-a-real-world-test

• Debunking Common Myths in Common-Mode Choke Measurements with a VNA
  Not all VNA measurements tell the full story. This article breaks down why differential-mode S21 tests often misrepresent common-mode suppression and how to properly measure common-mode impedance (Zcm) using correct setups and industry-aligned practices. It’s essential reading for anyone serious about validating choke performance.
  https://shop.rf.guru/pages/debunking-common-myths-in-common-mode-choke-measurements-with-a-vna

• RX vs TX Grounding — Totally Different Games
  Grounding for receive and transmit systems serves very different goals. This article explores why RX chains often benefit from high-impedance paths and localized grounding for EMI rejection, while TX systems demand low-impedance, high-current-capable grounds for safety and efficiency. Applying the wrong grounding strategy can compromise both performance and protection.
  https://shop.rf.guru/pages/rx-vs-tx-grounding-totally-different-games

• QRP Z-Match vs QRP Autotuner with Doublet and 600-Ohm Open Wire – Is a Z-Match More Efficient?
  Not all tuners are created equal. This article compares a traditional QRP autotuner setup with a 450-ohm line against a balanced Z-match paired with a 600-ohm open-wire-fed doublet. It shows how the Z-match offers better efficiency, broader tuning range, and lower system losses—especially critical in low-power operations.
  https://shop.rf.guru/pages/qrp-z-match-vs-qrp-autotuner-with-doublet-and-600-ohm-open-wire-is-a-z-match-more-efficient

• The 10 Worst Ham Radio Antennas of All Time
  We saved this one for last—for a reason. It’s not your usual technical breakdown, but a satirical look at some hilariously bad (yet surprisingly popular) antenna designs. From the “Fence Line Special” to the “Random Longwire of Doom,” this lighthearted listicle pokes fun at the shortcuts and myths that plague the ham world. A great cooldown read after all the heavy RF theory.
  https://shop.rf.guru/pages/the-10-worst-ham-radio-antennas-of-all-time

Team RF.Guru
Engineering the signal. Empowering the operator.