[ChrisJ7903] has created two Ardiuno programs for reading Victron solar controller telemetry data advertised via BLE. If you’re interested in what it takes to use an ESP32 to sniff Bluetooth Low Energy (BLE) transmissions, this is a master class. The code is split into two main programs. One program is for the Victron battery monitor […]
The ARRL used to have a requirement that any antenna advertised in their publications had to have real-world measurements accompanying it, to back up any claims of extravagant performance. I’m told that nowadays they will accept computer simulations instead, but it remains true that knowing what your antenna does rather than just thinking you know […]
Metalized Mylar “space blankets” are sold as a survivalist’s accessory, primarily due to their propensity for reflecting heat. They’re pretty cheap, and [HamJazz] has performed some experiments on their RF properties. Do they reflect radio waves as well as they reflect heat? As it turns out, yes they do. Any antenna system that’s more than […]
The world’s militaries have always been at the forefront of communications technology. From trumpets and drums to signal flags and semaphores, anything that allows a military commander to relay orders to troops in the field quickly or call for reinforcements was quickly seized upon and optimized. So once radio was invented, it’s little wonder how […]
In these days of everything-streaming, it’s great to see an old school radio build. It’s even better when it’s not old-school at all, but packed full of modern ICs and driven by a micro-controller like the dsPIC in [Minh Danh]’s dsMP3 build. Best of all is when we get enough details that the author needs […]
Impedance matching is one of the perpetual confusions for new electronics students, and for good reason: the idea that increasing the impedance of a circuit can lead to more power transmission is frighteningly unintuitive at first glance. Even once you understand this, designing a circuit with impedance matching is a tricky task, and it’s here […]
One of the first things that an amateur radio operator is likely to do once receiving their license is grab a dual-band handheld and try to make contacts with a local repeater. After the initial contacts, though, many hams move on to more technically challenging aspects of the hobby. One of those being activating space-based […]
While ham radio operators have been embracing digital mobile radio (DMR), the equipment is most often bought since — at least in early incarnations — it needs a proprietary CODEC to convert speech to digital and vice versa. But [QRadioLink] decided to tackle a homebrew and open source DMR modem. The setup uses a LimeSDR, […]
Would-be spooks and spies, take note: this one-transistor FM transmitter is a circuit you might want to keep in mind for your bugging needs. True, field agents aren’t likely to need to build their own equipment, but how cool a spy would you be if you could? Luckily, you won’t need too many parts to […]
If you paid attention to advertising in 1980s Britain, you were never far from Economy 7. It was the magic way to heat your house for less, using storage heaters which would run at night using cheap electricity, and deliver warmth day-long. Behind it all was an unseen force, a nationwide radio switching signal transmitted […]