Follow the Evidence, Follow the Current.
This month begins with a question about the writing itself: why do we spend so much time defining terms, naming reference planes and checking what a demonstration actually establishes? Because those details are where a useful observation becomes an explanation another amateur can test.
The November reading bench ranges from HF noise and NVIS to coax shields, ferrite cores and the future of 23 cm operation in Belgium. There is also a voyage across the Atlantic—and, at the end, a little club-room satire.
Read: Why We Write the Way We Do at RF.Guru
A lower displayed noise level is useful only when we know what happened to the wanted signal too. This article returns to the quantities behind a receive comparison: noise factor, signal-to-noise ratio and the decibel arithmetic that connects them. Keep the bandwidth and measurement point fixed before deciding which change improved reception.
Read: HF Noise Factor, SNR and Decibels
My short split-screen loops favoured floating shields; a larger loop on the ground benefited from an RC reference. Those results can coexist because electrical size, balance and the available common-mode paths change with the installation. The right connection is the one supported by measurements of that loop in that setting.
Read: Shielded Receive Loops—Floating Shields, Grounding and Common Mode
Ben Witvliet and his co-authors measured how ordinary and extraordinary waves return on near-vertical HF paths. Their work offers a more interesting result than a blanket claim that one polarization always wins: receiving distinguishable characteristic-wave channels can provide diversity when their fading differs.
Read: Ben Witvliet’s NVIS Circular-Polarisation Research
Touching a connector and watching an analyser trace change is an observation worth investigating. Your hand also changes the electrical surroundings of the test. Before treating that change as proof of one particular current path, repeat the experiment with controlled connections and a measurement aimed at the suspected mechanism.
Read: Your Body Is Not a Line Isolator
A coax-shield experiment can show impressive screening: broadcast signals disappear when the connector shell makes contact. That says something useful about the test setup. It does not, on its own, measure current on the outside of the cable. Shield effectiveness and common-mode current need separate tests.
Read: Coax Shield Test—Screening vs Common-Mode Current
Jacek Pawlowski, SP3L, raises a valuable measurement question: what happens when the fixture gives intermediate points on a choke winding a path to its RF reference? A full Y21 conversion can separate ideal shunts at the terminals, but it cannot generally undo a change to the network inside those terminals. The geometry of the test belongs in the result.
Read: SP3L, Stray Capacitance and the Limits of Y21 Choke Measurements
A single-wire surface-wave line makes a fine demonstration precisely because it works without inventing missing physics. Follow the electromagnetic fields, launch structure and surrounding return path, and the apparent paradox becomes an engineering problem you can describe and measure.
Read: Goubau Line—Single Wire and Return Path
Following a transmitter, tuner, feedline and antenna through one power budget means using the same definition of power at each boundary. A forward-power example cannot quietly become a net-accepted-power example while both still appear to start with the same 100 W. The article also examines what ALC and a remote tuner can—and cannot—promise.
Read: KJ6ER Primer 2—Power Accounting, ALC and Remote Tuners
Changing radials or adding a reflector can improve the signal in a useful direction. Directional gain is valuable, but a peak EIRP figure is not a count of extra watts radiated in every direction. This second response to Primer 2 keeps model assumptions, efficiency and comparison antennas attached to their figures.
Read: KJ6ER Primer 2—Radials, Gain, Efficiency and EIRP
Both references are legitimate when clearly stated. For practical antenna comparisons, I prefer the half-wave dipole as a baseline: it makes the gain claim answer a familiar engineering question. Converting units is straightforward; comparing the same direction, conditions and kind of gain takes more care.
Read: dBi vs dBd—Why I Use the Dipole Reference
A wire, coax and choke can make two antennas look alike in a photograph. Their feed arrangements and radiating surfaces tell the more useful story. Follow where the power enters and how current flows before assigning either design the behaviour of the other.
Read: EFOC vs T2LT—Antenna Current Paths
Additive manufacturing could free RF designers from the catalogue of standard core shapes. A printed Ni–Zn ferrite still has to deliver suitable magnetic properties, loss, consistency and power behaviour at the intended frequency. This research piece asks what a new geometry could offer and which tests would make it useful in an antenna system.
Read: Printed NiZn Ferrite Core Geometry for RF Antennas
A frequency move affects more than the number programmed into a transmitter. The article examines the proposed 23 cm rearrangement, Galileo-related limits, radar interference and what migration would mean for Belgian ATV repeaters and the viewers who rely on them. Occupied bandwidth, receive paths and national authorization all matter.
Read: 23 cm Radar, Belgium, ATV and Repeater Coverage
In 1974, three men set out from Morocco aboard a steel raft bound for Trinidad. Over 82 days, ON4AXA/MM gave radio amateurs ashore a callsign to follow and a voice to recognize. This story brings together a listener’s remembered 20-metre contacts and the contemporary radio record of an extraordinary crossing.
Read: ON4AXA/MM—The Belgian Raft That Crossed the Atlantic
Mark, K3ZD—Ham Florida Man—brings the practical demonstrations and sharp questions. The featured-video page connects his commentary to the relevant RF.Guru articles, so you can watch the example, follow the argument and check what still depends on the installation.
Watch: Ham Florida Man × RF.Guru—Featured Videos
Conrad Copy’s remarkable filter passes advice, drawings and useful corrections while removing every name attached to them. This fictional story is a gentle reminder that a source link or one honest sentence of acknowledgement makes technical work easier for the next person to trace.
Read: Conrad Copy and the Perfect Attribution Filter
Thanks for reading, testing and sharing what you learn. A good RF explanation leaves enough of the path visible for someone else to follow it.
Keep building. Keep measuring. Keep the names and the reference planes connected.