August: Meters, Meshes, and the Trouble with Counting Only Watts
For a while, the RF.Guru newsletter arrived twice a month. That gave us a faster rhythm — and gave your inbox an excellent opportunity to develop its own form of common-mode current.
Starting with this August edition, we are moving to one larger monthly newsletter containing 15 selected articles. The technical depth stays the same, but there will be fewer interruptions and a little more time to read one issue before the next one appears.
This month’s collection has a remarkably consistent theme: a number can be useful without being the whole explanation. Watts at the radio are not watts in the useful radiation pattern. A low SWR does not certify an antenna. A CE logo does not validate every possible hardware configuration. And a 10% airtime setting does not magically turn an SRD network into scalable infrastructure.
So the August theme is simple: measure the right thing, ask what the number represents, and never confuse one point in the system with the whole station.
What Makes a Bird Meter a Bird Meter?
It is not the logo, the case, or service-bench nostalgia. It is a calibrated directional wattmeter system built around a controlled 50-ohm line and interchangeable elements that measure forward and reflected power.
🔗 https://shop.rf.guru/pages/what-makes-a-bird-meter-a-bird-meter
Is the Watt Scale on an SWR Meter Just Ohm’s Law at 50 Ohms?
The scale is rooted in the familiar 50-ohm power relationship, but the meter is not simply watching a resistor. It samples traveling waves, detects them, and relies on calibration to turn that sample into a watt reading.
🔗 https://shop.rf.guru/pages/is-the-watt-scale-on-an-swr-meter-just-ohm-s-law-at-50-ohms
Stop Thinking in Watts: Start Thinking in dB
Watts make impressive front-panel numbers. Decibels reveal how much difference remains after feedline loss, matching loss, antenna efficiency, radiation pattern, propagation, and the receiving station all get a vote.
🔗 https://shop.rf.guru/pages/stop-thinking-in-watts-start-thinking-in-db
Your 100 W Radio Is Not a 100 W Station
The rating belongs to the connector on the back of the radio. The station includes every jumper, meter, tuner, transformer, feedline, return path, antenna loss, and unintended current between that connector and the useful signal.
🔗 https://shop.rf.guru/pages/your-100-w-radio-is-not-a-100-w-station
When a Repeater Antenna Is Too Close to the Roof
Good SWR and impressive catalogue gain do not guarantee good coverage. A nearby roof can reshape the elevation pattern, scatter energy, and create coverage holes — especially when a multi-section collinear is installed without enough electromagnetic breathing room.
🔗 https://shop.rf.guru/pages/when-a-repeater-antenna-is-too-close-to-the-roof
A Gamma Match Is Still a Match
A gamma match can transform the feedpoint impedance and make the transmitter happier. It does not automatically improve gain, efficiency, front-to-back ratio, or the emotional wellbeing of the Yagi elements.
🔗 https://shop.rf.guru/pages/a-gamma-match-is-still-a-match
1/4-Wave Fan Verticals
Several intentional quarter-wave radiators can share one feedpoint and radial system, giving each band its own useful current path without traps or loading coils. Simple in concept — but coupling, spacing, environment, and final tuning still matter.
🔗 https://shop.rf.guru/pages/1-4-wave-fan-verticals
Cosmic Radiation, HF Interference, and QRO Stations
Cosmic particles, solar effects on the ionosphere, receiver interference, and RF exposure all involve the word “radiation,” but they are not the same physical problem. This article separates ionizing radiation, propagation disturbances, and the practical near-field risks of a QRO station.
🔗 https://shop.rf.guru/pages/cosmic-radiation-hf-interference-and-qro-stations
Common-Mode Current Radiation
Common-mode current does more than disturb patterns and crash computers. When unwanted RF reaches the coax exterior, mast, shack wiring, microphone, desk, or operator, it can create localized exposure, RF burns, and very real safety problems.
🔗 https://shop.rf.guru/pages/common-mode-current-radiation
5G Microcell or 1.5 kW HF Station
The service name does not determine the hazard. Power, antenna gain, direction, distance, frequency, duty cycle, near-field conditions, and unintended current paths determine what field actually reaches a person.
🔗 https://shop.rf.guru/pages/5g-microcell-or-1-5-kw-hf-station
Meshtastic, MeshCore, CE Marking, and the Hardware Trap
A familiar chipset, working firmware, European warehouse, or CE-like logo in a webshop photo does not prove that the exact radio product and antenna configuration are compliant. The complete hardware implementation still matters.
🔗 https://shop.rf.guru/pages/meshtastic-meshcore-ce-marking-and-the-hardware-trap
Meshtastic, MeshCore, and the Legal Framework
Every packet belongs to a regulatory framework. On European 868/869 MHz, a callsign does not transform SRD operation into amateur radio, and software airtime limits do not certify the transmitter, antenna, emissions, or complete installation.
🔗 https://shop.rf.guru/pages/meshtastic-meshcore-and-the-legal-framework
Why a 10% Airtime Mesh Network Will Always Hit the Wall
Ten percent can look generous for one quiet tracker and become hopeless for a busy relay carrying everyone else’s traffic. Per-device legality does not create network capacity, prevent collisions, or make an SRD channel scale like amateur infrastructure.
🔗 https://shop.rf.guru/pages/why-a-10-airtime-mesh-network-will-always-hit-the-wall
Open Winlink for IARU Region 1
A proposal for coordinated VHF radio-email operation today and a more open modem stack tomorrow. The goal is not another isolated digital mode, but predictable channels, visible coordination, open clients, and a path beyond closed modem dependency.
🔗 https://shop.rf.guru/pages/open-winlink-for-iaru-region-1
When Big-Box Antenna Content Sounds Like AI
Tidy headings, confident sentences, and a respected logo can still rebuild old antenna myths. A close reading of a polished radials guide shows why authoritative tone is never a substitute for defined return paths, careful terminology, and actual RF context.
🔗 https://shop.rf.guru/pages/when-big-box-antenna-content-sounds-like-ai
Finished all 15 articles? Grab a coffee, lean back, and let Mark’s warm voice take over.
Our collaboration with Mark — K3ZD (“Ham Florida Man”) brings many of these RF topics to life through calm explanations, practical measurements, and a refreshing shortage of magical thinking.
🔗 Watch the featured videos from our collaboration
If this first monthly edition leaves you asking “watts where?”, “CE for which exact configuration?”, and “what is the rest of the station doing?” — good.
Numbers are useful. Systems decide what those numbers actually mean.
73,
Joeri – ON6URE
Founder – RF.Guru
https://rf.guru/