Collaborate Disseminate
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, …read more Continue reading Homebrew TEM Cell Lets You EMC Test Your Own Devices
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 …read more Continue reading When Does Impedance Matching a PCB Trace Become Unavoidable?
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 …read more Continue reading The Dipole Antenna Isn’t as Simple as it Appears
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 …read more Continue reading Measuring Impedance Virtually
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 physical layer …read more Continue reading Hacker Dictionary: RS-485 Will Go the Distance
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, …read more Continue reading Impedance Mismatch
Using circuit simulating software like SPICE can be a powerful tool for modeling the behavior of a circuit in the real world. On the other hand, it’s not always necessary to have all of the features of SPICE available all …read more
Continue reading Circuit Impedance Calculations Without Cumbersome Simulations
So far in the $50 Ham series, I’ve concentrated mainly on the VHF and UHF bands. The reason for this has to do mainly with FCC rules, which largely restrict Technician-level licensees to those bands. But there’s a financial component …read more
Continue reading The $50 Ham: A Cheap Antenna for the HF Bands
“Time-domain reflectometry” sure sounds like something that needs racks of expensive equipment to accomplish. In reality, TDR is just measuring the time between injecting a pulse into a cable and receiving its echo, either from the other end of the cable or from some fault or defect along the way. …read more
Continue reading Dead Simple Time-Domain Reflectometry with Just a Battery and an Oscilloscope
At DC and low frequency, we can pretend wires are perfect conductors. At radio frequencies, though, there are many effects that you need to take into account for wires and cables. One of these is characteristic impedance. If you have a marked cable, you can look it up on the …read more