Few Things Are Cheaper Than This Antenna

As far as hobbies go, ham radio tends to be on the more expensive side. A dual-band mobile radio can easily run $600, and a high-end HF base station with the capability of more than 100 watts will …

A Simple Guide To RF PCB Design

[Hans Rosenberg] knows a thing or two about RF PCB design and has provided a three-part video demonstration of some solid rules of thumb. We will cover the first part here, and leave the other two …

Coax Stub Filters Demystified

Unless you hold a First Degree RF Wizard rating, chances are good that coax stubs seem a bit baffling to you. They look for all the world like short circuits or open circuits, and yet work their ma…

Homebrew TEM Cell Lets You EMC Test Your Own Devices

Submitting a new device for electromagnetic compatibility (EMC) testing seems a little like showing up for the final exam after skipping all the lectures. You might get lucky and pass, but it reall…

When Does Impedance Matching A PCB Trace Become Unavoidable?

A common joke in electronics is that every piece of wire and PCB trace is an antenna, with the only difference being whether this was intentional or not. In practical terms, low-frequency wiring is…

The Dipole Antenna Isn’t As Simple As It Appears

Dipole antennas are easy, right? Just follow the formula, cut two pieces of wire, attach your feedline, and you’re on the air.  But then again, maybe not. You’re always advised to cut t…

Measuring Impedance Virtually

We always enjoy a [FesZ] video and we wonder if the “Z” stands for impedance? That’s the topic of his latest video series: measuring impedance with LTSpice. Of course, he also doe…

Hacker Dictionary: RS-485 Will Go The Distance

RS485 is a communication standard that should be part of the advanced hardware hacker’s arsenal; it’s not commonly encountered, but powerful exactly when you need it. It’s a physi…

Impedance Mismatch

There are a few classic physics problems that it can really help to have a mental map of. One is, of course, wave propagation. From big-wave surfing, through loudspeaker positioning, to quantum mec…