LDMOS amplifiers

Pete (N6QW) writes: This project encompasses proving an Arduino Control of a hi Power Linear Amplifier. It is a new departure for N6QW as it has extensive I/O requirements which required moving to the Mega 2560 a Arduino variant that has 56 Digital I/O and 16 Analog Inputs. The on board memory is 256K The […]

Crystal motional parameters

Craig writes: Ever tried searching through your datasheets for the motional parameters of that quartz crystal you just bought? Good luck! Vendors simply don’t specify these parameters to general end users, and for most applications that’s OK. But for high Q oscillator and filter design, measuring and matching crystals can be important. This video discusses […]

Simple crystal tester

Dilshan Jayakody writes: This is simple Colpitts oscillator to test commonly available passive crystals which range between 2MHz to 27MHz. This unit must connect to an oscilloscope and/or frequency counter to get the frequency of the crystal. This circuit is design to work around 9V to 12V DC power source. Both 2SC930 transistors can replace […]

Building a better RTL-SDR TCXO

Craig posted an article describing how he built a 28.8MHz RTL-SDR TCXO, that is available on github: Here’s a scratch-built 28.8MHz TCXO capable of +-1ppm stability from 0C-55C; best of all, it’s not only easy to build, but is designed entirely from readily available and inexpensive components. For improved temperature stability, the main oscillator can […]

The Sproutie “SPT” Beacon – A legal, unlicensed HiFER beacon

Dave Richards (a.k.a. AA7EE) has written an article detailing his “SPT” Sproutie HiFer beacon project: My first “proof of concept” at putting together a beacon for this band was to connect an N0XAS PicoKeyer in beacon mode to my Pixie 2 transmitter. With the PiicoKeyer, if you insert the prosign BN at the end of stored […]

TI Design Contest: Envision the ultimate NFC wearable

TI has announced a contest for NFC based wearable designs. Do you dream of creating a solution to make monitoring health and fitness activities easier? Using near field communication (NFC) in your designs can help! We want to hear your ideas for the next wearable design based on our RF430FRL15xH NFC sensor transponder in our […]

Sniffing Crazyflie’s radio with HackRF blue

arnaud acquired a HackRF Blue and has been busy coding up a GNURadio project for analyzing Crazyflie radio transmissions. Crazyflie is a nano quadcopter/drone controlled over a wireless link. The Crazyradio is the official radio dongle for the Crazyflie Nano Quadcopter. It is a 2.4GHz USB radio dongle based on the nRF24LU1+ chip from Nordic […]

YOUSDR remote RTL-SDR software

Sixuniform has released YOUSDR v0.1 Alpha, an RTL-SDR webinterface for Raspian / Raspberry Pi. This is a web-wrapper for the rtl-sdr softwares. Currently it commands rtl_fm, rtl_tcp and dump1090. The software can be downloaded from its GitHub. The instructions on the GitHub page show how to set it up on a Raspberry Pi running Raspbian, […]

Tektronix RSA 306 – GPS receiver and clock reference

KF5OBS writes, “The Tektronix RSA 306 is a great low-cost USB 3.0 spectrum analyzer for up to 6 GHz in an ultra low-profile format. If paired with the RSA Map function of SignalVu-PC and a GPS receiver, it becomes an extremely powerful tool for interference hunting and signal strength mapping. This article shows a possible way […]

OpenSprinkler Firmware 2.1.1 new feature: Control remote power sockets

We previously covered Ray’s OpenSprinkler. Now it has added a new feature to remotely toggle radio frequency power sockets: This allows OpenSprinkler to not only switch sprinkler valves, but also easily control powerline devices such as lights, heaters, pumps, fans. Looking for a programmable way to control Christmas lights? Look no further! This feature is […]

Reverse engineering a Verisure wireless alarm

Here’s an informative two-part series of posts over at FunOverIP detailing how to reverse engineer a Verisure wireless alarm. Part 1 details the beginning steps such as finding the modules radio frequency and modulation type, analyzing the chipset datasheet and using GNU Radio.

Viewing a VHS tape using RTL-SDR and TV Sharp software

Here’s a different and unconventional way to view a VHS tape (as if VHS tapes aren’t considered unusual enough today). DogsRNiceMineCraft posted this video on YouTube showing video received using an RTL-SDR dongle. I got a VCR today and wanted to see if I could receive the signal from the RF out using TV sharp. […]

Introducing RFToy, an Arduino-compatible gadget for radio frequency modules

Ray Wang from RaysHobby has informed us of his latest open-source project called RFToy: it’s an Arduino-compatible microcontroller board for interfacing with radio frequency (RF) modules, such as the popular 433/315MHz transmitter/receiver, and the nRF24L01 transceiver. The RFToy has a built-in ATmega328, USB-serial converter (CH340G), 128×64 OLED display, three buttons, and a coin battery holder. Programming […]

Video: FlexRadio open API

During the TAPR/ARRL Digital Communications Conference in Austin last September, Stephen Hicks N5AC gave this presentation on interfacing with FlexRadio using their open API. Part II of this presentation was given by Graham Haddock KE9H, and discussed the FlexRadio wavefrom API. It is available from HamRadioNow. FlexRadio produces a series of high-end SDR’s, with the […]

Project: extracting and geographically plotting DTRS site information

Lui Gough has been researching the Australian railroad system’s new digital radio system and has posted detailed observations: As a radio enthusiast, and highly observant public transport user, I’ve made many notes about the deployment of the new Digital Train Radio System (DTRS) sites. This new system is based upon GSM-R in the 1800Mhz band, […]

Mastervolt soladin RF filtering

Brian Dorey writes: Following from the Mastervolt Soladin 600 Inverter RF Interference post about the major RF interference problems generated by the Mastervolt Soladin 600 tie-in mains inverter we have now resolved the RF interference by replacing the unscreened and unearthed plastic case on the inverter with an earthed metal case and installed filters on […]