Category: RF
Inverter crystal oscillator
Vasily Ivanenko build some discrete chip oscillators with 74HC series logic gates and tests them on his oscilloscope. He writes: In numerous RF synthesizer chips lies an inverter with input and output pins for making a reference crystal oscillator clock. I built some discrete chip...
Continue ReadingVXO – based PLL frequency synthesizer for 7 MHz
Vasily Ivanenko made a VXO-based synthesizer: To make a VXO to mix with a ~7 MHz VCO, you’ll need a crystal that is higher in frequency than the highest frequency you want to synthesize. Some rummaging revealed a bag of 21.4773 MHz crystals that I could divide by 3 to garner 7.159...
Continue Reading4 Channel RF Remote Controller
4 Channel RF remote built using PT2262 and PT2272-M4 IC from Princeton technology. PT2262 used as Encoder (Transmitter) and PT2272-M4 Decoder (Receiver) ICs are heart of the project. The receiver provides 4 channel Momentary outputs. All outputs are TTL level can be interface with...
Continue ReadingDIY 1GHz Active Probe For Under 20$
thirschbuechler @ instructables.com shows us how to build a 1GHz active probe using BF998 dual-gate MOSFET and some other RF components. This Instructable will show you how to build a 1GHz* Fet-based Active Probe, the Fetprobe, for about 10$*, provided you have access to an...
Continue ReadingHow to do serial comms using the cheap RF 433/315 MHz modules
RomanBlack.com explains in details how to use 433/315Mhz modules for serial communication. These cheap RF modules usually come in a pair, with one transmitter and one receiver. A pair can be bought on ebay for as cheap as $4, and even as cheap as $2 a pair if you buy 10...
Continue ReadingDIY electronic RFID Door Lock with Battery Backup
Elmue build a RFID electronic door lock using PN532 Controller, Vehicle Battery and Teensy 3.2 board. The advantage of an electronic door lock is that the above security issues do not apply. It is much better to have a safe door lock which prevents that the thief can enter than to...
Continue Reading28.8MHz TCXO with +-1ppm Stability
Craig document his process of building a Better RTL-SDR TCXO with +-1ppm stability over 0C-55C range. Its hard to beat the cost and versatility of the ubiquitous RTL-SDR dongles, but the temperature stability of their reference oscillators isn’t sufficient for some applications....
Continue ReadingRF Isolator: Teardown and Experiments
In this video, Kerry Wong took apart a 8 to 10 GHz microwave RF isolator and did some measurements. High resolution teardown pictures here. RF Isolator: Teardown and Experiments -...
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