Ondrej Karas of DoItWireless writes:
This is simple illustration how to build easy PWM LED control with IQRF TR module and a few other components.
This device is powered from 12V/6A DC power supply and can power up to 5m of LED strip. This device can be controlled via RF, buttons or potentiometer. RF controlling is compatible with remote control device RC-04 with low battery signalizing – fast 3 time LED blinking.
RF PWM LED control - [Link]
As promised we have built a transceiver USB dongle, for receiving data from various sensors like, smart meters, smoke detectors and temperature/humidity sensors. We’ll provide some code examples on how this trasciever can be used, and software for decoding data from diferent sensors enumerated above.
USB RF 433.92 MHz Transceiver module - [Link]
Instructables user Slomi posted this useful project on how to build a wireless indoor and outdoor thermometer using an Arduino! Via Embedded Lab.
This Arduino-based wireless thermometer uses two Arduino boards to measure indoor and outdoor temperatures. The outdoor Arduino board sends out the outdoor temperature measured by DS18B20 sensor to the indoor Arduino board using inexpensive 433MHz RF transmitter and receiver modules. The indoor Arduino board then displays the indoor and outdoor temperatures on a character LCD display.
Indoor/outdoor wireless thermometer using Arduino - [Link]
An introduction to why and when terminations are needed for transmission lines in both high speed digital applications and RF applications. 50 ohm termination examples are given, but the principles apply for other line impedances as well. The basic operating principles of signal propagation down a transmission line and the effects of reflections coming from improperly terminated are covered. Examples for digital-like signals as well as RF signals are given. A description and examples of what is meant by Standing Waves is also given. As a bonus, the properties of quarter wavelength transmission lines in RF applications is also presented.
Transmission Line Terminations for Digital and RF signals - [Link]
High-performance RF signal source family offers AM/FM/Phase modulation with I/Q modulation option
Fairport NY: Saelig Company Inc. (www.saelig.com) has introduced a high-performance RF signal source family, the DSG3000 3GHz/6GHz series, offering standard AM/FM/Phase modulation, as well as options for I/Q modulation and I/Q baseband output. The DSG3000 Series generates waveforms with high signal purity, typical phase noise of less than 110dBc/Hz@20kHz, and a wide output range of -130dBm to +13dBm. The DSG3000 RF signal generator has standard pulse modulation with an on/off ratio of up to 80dB, with an optional pulse train generator also available. The DSG3000 series has a typical amplitude accuracy of better than 0.5dB, and the standard 0.5ppm internal clock can be upgraded to an optional 5ppb high stability oven-controlled clock.
The DSG3000 series RF signal generators support internal and external modulation capabilities and operate with USB, LAN, LXI-C, and GPIB remote control interfaces. They also feature a wear-free electronic attenuator design and an automatic flatness calibration function via external automated power meter control over USB. This can be used as an automatic flatness calibration test system functionality for cables, attenuators, amplifiers, etc. The DSG3000ʼs standard 2U height is designed to save space when used with the optional rack mount kit.
Offering remarkable value for the money, the DSG3000 Series RF source is ideal for applications in wireless communication, radar test, audio/video broadcasting, as well as for general purpose, educational, and consumer electronics needs.
DSG3000 Signal Generators are made by RIGOL Technologies, a rapidly growing test and measurement company and the worldʼs second largest oscilloscope manufacturer by volume. RIGOL delivers high quality, high performance and value-priced test equipment for engineers, technicians and students worldwide. Offered with a remarkable 3-year warranty, the DSG3000 series is available now from Saelig Company, Inc. 1-888-772-3544 email@example.com
Saelig Announces Economical 3GHz/6GHz RF Signal Generator Series - [Link]
What’s inside Tektronix’s new MDO3000 Mixed Domain Oscilloscope? Dave does a teardown and looks at the circuitry and how they can get such a cheap 3GHz RF spectrum analyser to work.
EEVblog #587 – Tektronix MDO3000 Mixed Domain Oscilloscope Teardown - [Link]
Ever wondered how they transmit your TV signal?
David Kilpatrick from TXAustralia takes us on a detailed tour of the old decommissioned 10kW analog TV transmission system at the Artarmon facility in Sydney. It is still used to transmit digital TV. How it all works from the broadcaster video input to final transmission output up the 180m broadcast antenna. Plus some teardowns of the old equipment that’s been used to transmit the Channel 7 TV signal in Sydney since 1981.
Copper rigid coaxial lines, waveguides, filters, splitters, combiners, converters, transmission valve, power supplies and all the equipment necessary to transmit a 10kW analog or digital TV signal in a major city like Sydney.
EEVblog #569 – Tour of an Analog TV Transmission Facility - [Link]
Ray Wang writes:
Hi, I recently built a reflow toaster oven using an Arduino. I know it’s pretty standard stuff, but my version has an automatic oven door opener (using a servo) and circulation fan to speed up the cooling time, and remote notification using an RF transmitter
Reflow toaster oven using an Arduino - [Link]
By Bill Schweber:
In a wireless design, two components are the critical interfaces between the antenna and the electronic circuits, the low-noise amplifier (LNA) and the power amplifier (PA). However, that is where their commonality ends. Although both have very simple functional block diagrams and roles in principle, they have very different challenges, priorities, and performance parameters.
How so? The LNA functions in a world of unknowns. As the “front end” of the receiver channel, it must capture and amplify a very-low-power, low-voltage signal plus associated random noise which the antenna presents to it, within the bandwidth of interest. In signal theory, this is called the unknown signal/unknown noise challenge, the most difficult of all signal-processing challenges.
Understanding the Basics of Low-Noise and Power Amplifiers in Wireless Designs - [Link]
By Bill Schweber
The explosive growth of “wireless” systems has led to a simultaneous expansion in the use of RF connectors and their associated cables. These assemblies are increasingly vital links between multiple circuit boards, between antennas and front ends, and between power amplifiers (PAs) and antennas. They are instrumental to the operation of such wireless devices and systems as cellular telephones, wireless data networks and advanced radar and electronic-warfare (EW) systems.
Connectors for RF systems have the simple yet critical task of transferring signals from one location to another, with little or no change to the signal (although in reality even with high quality RF cable between the antenna connector and the antenna engineers often factor in a 0.2 dB loss per coaxial connector in addition to the cable attenuation itself).
Selecting an RF Connector for your Wireless System - [Link]