“It Depends.” Because RF Doesn’t Care About Simple Answers
By the end of February, the band conditions may change… but the questions do not. “Is my antenna balanced?” “Does grounding fix RF?” “Can I measure efficiency with my VNA?” And the perennial favorite: “How long is too long?”
This issue is a guided tour through the parts of RF people love to oversimplify: balanced vs unbalanced, antenna impedance vs line impedance, feedlines that behave like current machines, and why the environment is often the most important “circuit element” you forgot to model.
The core message is simple: if RF feels confusing, it’s usually because the setup is incomplete — not because the physics is mysterious.
Why You Can’t Measure Antenna Efficiency with a VNA
VNAs are great tools — but efficiency isn’t one of the things they can directly tell you.
Here’s why, and what measurements actually matter.
🔗 https://shop.rf.guru/pages/why-you-can-t-measure-antenna-efficiency-with-a-vna
Broadband HF Transformers
A practical look at what makes a transformer “broadband” in the real world — and what makes it quietly lossy.
🔗 https://shop.rf.guru/pages/broadband-hf-transformers
Why Feedlines Are “Current-Driven” in Normal 50-Ohm Operation
A key concept that explains half the misunderstandings around coax behavior, matching, and common-mode current.
🔗 https://shop.rf.guru/pages/why-feedlines-are-current-driven-in-normal-50-ohm-operation
How Long Is Too Long?
Cable length debates never die. This one explains where length really matters — and where it’s just superstition.
🔗 https://shop.rf.guru/pages/how-long-is-too-long
It Depends!
The most correct answer in RF, and the one people hate hearing. Here’s why context is the answer, not a footnote.
🔗 https://shop.rf.guru/pages/it-depends
Off-Center-Fed Dipole ≠ “Unbalanced Antenna”
OCFs aren’t automatically “unbalanced.” What matters is the reference and the return paths you create.
🔗 https://shop.rf.guru/pages/off-center-fed-dipole-unbalanced-antenna
“Unbalanced Antenna” Usually Means “Unbalanced to Ground”
A phrase that causes endless confusion. This piece defines it properly — and shows why it matters for feedline current.
🔗 https://shop.rf.guru/pages/unbalanced-antenna-usually-means-unbalanced-to-ground
600 Ω Ladder Line on an Off-Center-Fed Dipole
The line can be beautiful. The environment can ruin it. Here’s what works, what doesn’t, and why.
🔗 https://shop.rf.guru/pages/600-ohm-ladder-line-on-an-off-center-fed-dipole
600 Ω Open-Wire Line: Balanced by Design, Unbalanced by the Environment
Balanced lines stay balanced only if the environment lets them. This explains how symmetry is lost in real installs.
🔗 https://shop.rf.guru/pages/600-ohm-open-wire-line-balanced-by-design-unbalanced-by-the-environment
Floating Ground in AC Power Has a Meaning … in RF It Mostly Doesn’t
In safety and power systems, “ground” has purpose. In RF, it’s usually an abused word for a return path you didn’t model.
🔗 https://shop.rf.guru/pages/floating-ground-in-ac-power-has-a-meaning-in-rf-it-mostly-doesn-t
DC-Grounded Coax at HF: Why “Ground” Doesn’t Tame RF
DC continuity is not an RF solution. Here’s why “grounding the shield” doesn’t automatically stop common-mode current.
🔗 https://shop.rf.guru/pages/dc-grounded-coax-at-hf-why-ground-doesn-t-tame-rf
Antenna Impedance vs. Transmission Line Impedance
Two different concepts that get blended into one argument. This separates them — and makes matching make sense again.
🔗 https://shop.rf.guru/pages/antenna-impedance-vs-transmission-line-impedance
Delta Loop vs Dipole Directionality
Directionality isn’t a slogan. It’s current distribution, height, and environment — and this compares the two properly.
🔗 https://shop.rf.guru/pages/delta-loop-vs-dipole-directionality
Measurement-Avoiditis
A chronic condition affecting many operators. Symptoms include absolute claims, zero measurements, and strong opinions.
🔗 https://shop.rf.guru/pages/measurement-avoiditis
Prefer seeing the measurements instead of debating them?
Mark breaks down many of these topics with calm explanations,
clear demonstrations, and zero tolerance for RF mythology.
🔗 Watch the featured videos from our collaboration
If you take one thing from this issue, let it be this: “balanced” and “unbalanced” only mean something when you say: balanced to what?
And when someone answers a complex RF question with a single sentence… it’s okay to reply: “It depends.”
73,
Joeri – ON6URE
Founder – RF.Guru
https://rf.guru/