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2 Jun 2012

www.vk4adc.com writes:

Getting into microwave but having problems finding an accurate method of measuring the RF power at these frequencies? If you are like me, you can’t afford to buy even a used HP 432, 435 or 436 version power meter via eBay. I have to admit I was tempted recently when I spotted a HP435A listed for here in Australia and then noted that there was no sensor with it. Quite a while later after searching eBay for sensors, I came away for a reality check – I might get the 435A for under $200 but a suitable sensor was going to cost somewhat more than $300. Sorry, but $500 doesn’t figure into my budget for a device which might be up to 40 years old, with calibration status unknown and sensor status questionable – and expensive to repair if damaged.

DIY Microwave RF Power Meter – 100MHz – 12GHz - [Link]

14 Mar 2012


The excellent book on transmitters that offer contains 467 pages of information in English about transmitters. Radio Transmitters was published in 1961 by engineers at the laboratory of ITT radio transmission.

Here’s a whole book dedicated to transmitters! Targeted at professional engineers rather than hams, this covers it all from oscillators through power amps, modulators, power supplies, and antenna matching.

Radio Transmitters – Tube power RF Circuits - [Link]

14 Mar 2012

Amitor 1.1 – toroidal core coils Calculator

The identification for the Amidon toroids consists of one or two letters (T=toroid and FT=ferrite toroid), followed by a number (for ex. T50), which represents the outer diameter dimension expressed in 0,1 inches, followed by a separation mark (dash, dot, stroke), followed by another number indicating the frequency mixture and the frequency range at which it would be recommended to use the toroid.

It should be taken in account that a toroid with a X declared frequency will be able to operate with fairly good performances even at 10 times higher frequencies and only the A factor will decrease.

The iron powder toroids are colored according to their mixture; the first color covers three sides and the second color the remaining side.

Bobcalc 2.0 – Simple air Coil Calculator

Simple software to calculate the air core coils, the most widely used in RF circuits and may use the software to determine the data to build a coil, knowing that the inductance of this coil. The software will give the result of how many turns will be required to achieve certain inductance value, and provides the wire diameter … In addition has a table with wires AWG mm thick.

Toroidal Coil + Simple Air Coil Calculator - [Link1]+ [Link2]

9 Mar 2012

The light weight, compact size and low cost DSA800 family of spectrum analyzers from Rigol Technologies feature digital IF technology to provide the reliability and performance necessary for RF applications. The spectrum analyzers have a frequency range of 9 kHz to 1.5 GHz with a typical displayed average noise level (DANL) of ‑135 dBm. SSB offset phase noise is typically -80 dBc/Hz at 10 kHz, and the resolution bandwidth is adjustable from 100 Hz to 1 MHz. A preamplifier and AM/FM demodulation are standard with this instrument. [via]

Low-Cost Spectrum Analysers Feature 1.5 GHz Top End - [Link]

29 Feb 2012

Sergei Bezrukov writes:

In this project we send and receive digital data by using a 433MHz transmitter and receiver modules TXM-433 and RXM-433 manufactured by LINX. We also use LINX helical whip-style antennas. The following images show the first part of the project – assembling the modules on a PCB and establishing RF connection between them.

Transmitting digital data over RF with LINX modules - [Link]

9 Feb 2012

Here’s an app note about a circuit for detecting and locating radio frequency transmitters.  The circuit is based around the MAX2015 RF detector which outputs a voltage proportional to the strength of a received RF signal in the 100 MHz to 3 GHz range – [via]

This design idea showcases a circuit that detects RF “bugs,” such as hidden wireless cameras, eavesdropping microphones, and other spying devices that emit RF frequencies in the 100MHz to 3000MHz range. A modification to this circuit not only detects RF bugs, but also locates their hidden positions.

App note: Detecting and locating RF bugs - [Link]

31 Jan 2012

open-electronics.org writes:

One of the first companies to focus on Wi-Fi was the AsyncLabs, who proposed a famous WiFi shield, including the appropriate libraries. What we propose is a new solution for Wi-Fi: this is a shield that the hardware was inspired by that of AsyncLabs, but in addition, we have provided a slot for microSD memory.

The basic component of the shield that we have made is a Wi-Fi module MRF24WB0MA manufactured by Microchip.  The device is a Wi-Fi IEEE 802.11 RF transceiver, with a data rate between 1 and 2 Mbps, and with an internal antenna.

The WiFi shield supports both types of wireless networks infrastructure (BSS) and ad-hoc (IBSS) and is also allowed to connect to secure networks (cryptographers and are supported 64 and 128-bit WEP, WPA/WPA2 and TKIP, AES and PSK).

The library is constantly evolving, so we have provided a space where they will be published on http://code.google.com/p/wifi-shield-oe/ various versions available. http://www.open-electronics.org/arduino-wifi-shield/

Arduino WiFi Shield - [Link]

10 Dec 2011

Stephen Evanczuk writes:

Micro-harvesting, or energy scavenging, relies on extracting power from minute but pervasive sources of ambient energy such as light, heat, RF, or vibration. With piezoelectric devices, energy from vibration can supply low-power applications, such as wireless sensors that are difficult to reach and maintain, for equipment or structural monitoring. By following a few key design considerations, engineers can build applications powered by piezoelectric transducers from Parallax, Measurement Specialties/Schaevitz, and Mide Technology and power management devices from Linear Technology.

Compared to other micro-harvesting energy sources, vibration and motion are relatively robust sources of ambient power (Figure 1). Placed on motors, for example, vibration-powered sensors can harvest power precisely when it is needed during motor operation. In a practical application, the piezoelectric transducer would likely be used to charge a high efficiency storage device rather than provide power directly to application circuits.

Energy Scavenging with Piezoelectric Transducers - [Link]

6 Dec 2011

Pittsford, NY, USA:  Saelig Company, Inc. has introduced WiPry-Combo – the worldʼs first dynamic power meter and spectrum analyzer accessory for the iPad, iPod Touch, and iPhone – offering a modern touch interface not available on PC-based instruments. WiPry-Combo turns an iOS device into an ultraportable spectrum analyzer and dynamic power meter.  WiPry-Combo brings RF power measurements to a graphical interface to show RF waveforms like an oscilloscope – instead of showing voltage, RF amplitude is displayed on an iOS portable device.  Actual power output can be triggered, captured, and recorded for protocol verification or for troubleshooting wireless devices. Data is collected at up to 12 MSa/s, allowing analysis and verification of the smallest protocol level on/off times. WiPry-Combo offers data logging in csv format, while screenshot results can be instantly emailed via the iOS host phone. 

In its Spectrum Analyzer mode, WiPry-Combo offers a practical solution for identifying interference or open channels in the 2.4GHz ISM band, or for identifying unauthorized WiFi access points.  Operating in the frequency range: 2.400 to 2.495 GHz, it measures signals from -40dBm to +20dBm with an amplitude resolution of 2.0dBm and a bandwidth resolution of 1MHz.  The band sweep time is 200ms. Read the rest of this entry »

26 Nov 2011

NXP Semiconductors has launched the CLRC663, the first member of a new generation of high-performance proximity contactless reader ICs. It combines robust multi-protocol support with the highest RF output power and patented low-power card detection technology. The CLRC663 is targeted at a wide variety of use scenarios, including banking, e-government, transport and mobile payment.

Supporting all 13.56-MHz contactless standards, NXP’s new reader IC is compatible with all established smart card, smart tag and smart label technologies, including NFC Forum tag types and Mifare products. It ensures best-in-class interoperability with smart cards, electronic documents and NFC-enabled phones based on NXP technology. [via]

Contactless card reader IC handles multiple protocols - [Link]





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