Collaborate Disseminate
Measuring a voltage is pretty easy: just place your multimeter’s probes across the relevant pins and read the value. Probing currents is a bit trickier, since you need to open …read more Continue reading Hackaday Prize 2023: Pi Pico Measures Volts, Amps and Watts
Dirty little secret time: although amateur radio operators talk a good game about relishing the technical challenge of building their own radio equipment, what’s really behind all the DIY gear …read more Continue reading Low-Cost RF Power Sensor Gets All the Details Right
The idea behind watts seems deceptively simple. By definition, a watt is the amount of work done when one ampere of current flows between a potential of one volt. If …read more Continue reading What’s in a Wattmeter?
If there’s one instrument that hams and other radio enthusiasts covet, it’s the venerable Bird 43 Thruline wattmeter. The useful RF tool has barely changed in the nearly 70 years …read more Continue reading Homebrew Wattmeter Pays Homage to Sturdy Original
Measuring power transfer through a circuit seems a simple task. Measure the current and voltage, do a little math courtesy of [Joule] and [Ohm], and you’ve got your answer. But what if you want to design an instrument that does the math automatically? And what if you had to do this strictly electromechanically?
That’s the question [Shahriar] tackles in his teardown of an old lab-grade wattmeter. The video is somewhat of a departure for him, honestly; we’re used to seeing instruments come across his bench that would punch a seven-figure hole in one’s wallet if acquired new. These wattmeters are …read more
Continue reading Old Wattmeter Uses Magnetics To Do the Math
When faced with a problematic Bird slug, [Chuck Martin] didn’t give up. He pecked away at the slug and brought us all along for the ride. If that sentence didn’t make sense to you, read on! Anyone who’s been to a hamfest has seen a Bird meter. The Bird Model 43 watt meter is the defacto standard for measuring transmitter power in-line. Bird meters don’t just work from DC to light though. In fact, the model 43 itself is just a bit of transmission line and a meter movement. The magic happens inside the swappable measurement element. These elements, affectionately …read more
If you buy an amateur transceiver cheap enough to make a reasonable grab bag gift or stocking stuffer, you get what you pay for. And if this extensive analysis of cheap radios is any indication, you get a little more than you pay for in the spurious emissions department.
Amateur radio in the United States is regulated by the FCC’s Part 97 rules with special attention given to transmitter technical specifications in Subpart D. Spurious emissions need to be well below the mean power of the fundamental frequency of the transmitter, and [Megas3300] suspected that the readily available Baofeng UV-5RA …read more
Continue reading Measuring Spurious Emissions of Cheap Handheld Transceivers
