Project Solutions (2011/07/25)
Index
Wave catcher （2）
Published:2011/7/25 22:53:00 Author:Phyllis
By Burkhard Kainka A longish wire Strong short-wave transmitters can be received using an aerial system’ (rod aerial or piece of wire) with a length of less than a meter. For long-distance reception, it is naturally much better to use a ’longish’ wire aerial, which preferably should be strung up outdoors - as widely separated from other objects as possible, as h... (View)
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DIY RF Inductors--The ABCs of inductors （7）
Published:2011/7/25 22:50:00 Author:Li xiao na
By B. Kainka Measurements If you do not have a suitable signal generator or dip meter, the only way to measure the resonant frequency of a resonant circuit is to use an oscilloscope. The frequency can be measured by exciting the circuit so it oscillates freely (Figure 8). This requires a steep-edge... (View)
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Wave catcher （1）
Published:2011/7/25 22:46:00 Author:Phyllis
By Burkhard Kainka Aerials and preselectors for AM and DRM For initial experimenting and radio listening with a DIY short-wave or DRM receiver, a simple rod aerial or piece of wire is sufficient. But it’s only natural to want something better. This article gives you the right tips for better reception. In the UHF band, radio waves propagate essentially in a line-of-sight ... (View)
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DIY RF Inductors--The ABCs of inductors （6）
Published:2011/7/25 22:30:00 Author:Li xiao na
By B. Kainka Damping, Q and bandwidth If you know the value of the damping resistance for a resonant circuit, it’s easy to calculate the circuit’s Q factor, and thus its bandwidth. This following example shows how a specific problem can be solved using the LCFR program. Suppose you want to build an aerial filter for the medium-wave frequency of 1296 kHz (BBC, AM and DRM) usi... (View)
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Pandora＇s Sound & Music Box
Published:2011/7/25 22:07:00 Author:Phyllis
By Ken Bromham Recycle an old CD-ROM drive for (triggered) playback This project was originally conceived for model making applications as a cheap way to provide high quality audio playback in response to a trigger signal (typically from a pushbutton or PIR detector), but we’re pretty sure Elektor readers can find many other uses. The standard low cost soluti... (View)
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Wind Speed & Direction Meter with A Clever Touch （1）
Published:2011/7/25 3:04:00 Author:Amy
By G.Samblancat This ingeniously designed circuit may be just the ticket for those interested in weather observations, in particular, wind speed and direction. The clever bit about the instrument is that both wind speed and wind direction are measured with a single sensor: a rotational speed meter with three blades, one fitted with a small vane. One advantage of the specific d... (View)
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DIY RF Inductors--The ABCs of inductors （5）
Published:2011/7/25 2:52:00 Author:Li xiao na
By B. Kainka Some practical examples Suppose you want to wind a 330-/JH inductor for a medium-wave detector radio on a cardboard roll with a diameter of 42 mm. Further suppose that the wire diameter is 0.5 mm, so 100 turns will yield a coil length of 50 mm. Now you can simply try several different values, which ultimately yields a result of approximately 80 turns. For tuning the med... (View)
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Project C+ （2）
Published:2011/7/25 2:51:00 Author:Phyllis
The medium The choice of cable is vital in order to match the pulse profile to the characteristics of the transmission medium and thereby achieve the observed pulse acceleration. After much trial and error in the Elektor Electronics laboratory we concluded that a length of twisted-pair 100 Mbit/s Ethernet cable (CAT5) operated in the sub-hertz frequency range gave the most consistent re... (View)
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DIY RF Inductors--The ABCs of inductors （4）
Published:2011/7/25 2:48:00 Author:Li xiao na
By B. Kainka Inductor calculations using software A small Visual Basic (VB) program called LCFR has been written to make calculations for inductors and resonant circuits. The source and executable code for this program can be obtained free of charge from the Elektor Electronics website. The number is 030398-11, see this month’s Free Download... (View)
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Project C+ （1）
Published:2011/7/25 2:37:00 Author:Phyllis
Data comms beyond light speed Research papers by their nature are difficult for the average layman to understand. Here in the Elektor Electronics laboratory between the odd cup of coffee we spend much time studying scientific reports. A recent paper by a Japanese research group caught our eye because we were able to replicate the effects described using a very simple circuit and the resu... (View)
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DIY RF Inductors--The ABCs of inductors （3）
Published:2011/7/25 2:34:00 Author:Li xiao na
By B. Kainka Resonant circuits Although resonant circuits are the most important application for inductors, resonant frequency and damping are also significant when inductors are used for other purposes, For one thing, it’s important to recognize undesired resonances, and for another thing, it’s very easy to determine the value of an unknown inductor by using frequency measurement... (View)
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Transceivers With Embedded MCU&ADC Produced by Nordic
Published:2011/7/25 2:08:00 Author:Phyllis
The nRF905 transceiver and the nRF9E5 transceiver with MCU, ADC are launched by the Nordic VLSI ASA. The nRF9X5 components are designed for 430-950 MHz wireless transceiver applications in both industrial and domestic environments. Especially in security systems, wireless data transfer, automatic meter reading, car alarm systems, point-of-sale systems, sensors and various telemetry systems. The nRF9E5 and nRF905... (View)
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High-End-Preamp （7）
Published:2011/7/25 1:45:00 Author:Amy
By Benjamin Hinrichs Testing, testing, testing... and into the box Before inserting the microcontroller and the PGA2311 into their sockets and connecting the display, you should painstakingly check all the boards for incorrectly fitted components, dubious solder joints and solder bridges. The first test should be performed with the boards outside of the enclosure. To hold ... (View)
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