Engineer Sergii Zadorozhnyi website
Simple SolutionsEffective Length of Receiving Magnetic Loop Antenna
Part 1: Single-turn Wire Loop Antenna
Monday , 4, July 2016
Radio
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How to compare the efficiency of different receiving antennas? When comparing electric receiving antennas with each other the effective length of an antenna is used as a coefficient of ratio between the voltage induced on the open-circuited terminals of the antenna and the power of the electromagnetic wave at the receiving point. And note that effective length and geometrical length of electric antennas often differ. But how to compare the efficiency of electric and magnetic receiving antennas?
Read MoreThe German “GRAHN GS5-SE” antenna is not as effective as the “Olusha-10” – a feedback review of the anti-noise ferrite rod antenna “Olusha-10” working
Saturday , 1, September 2012 Radio Leave a commentA Moscow radio amateur sent a review of the “Olusha-10” anti-noise ferrite rod antenna working. He carried out comparative testing twice and made two audio recordings that confirm the ability of this antenna to suppress radio interference in the medium wave frequency range. The comparison was carried out with the standard telescopic antenna of the “Eton E1” radio receiver, an external wire antenna about 15 m long, as well as with the loop and ferrite modules of the German active antenna “GRAHN GS5-SE”.
Read MoreEngineers and radio amateurs are interested in the static parameters of JFETs (Junction gate Field Effect Transistor), such as the zero-gate voltage drain current (IDSS) and the gate-to-source cutoff voltage (VGS(off)), as a rule, either when choosing JFET with the best parameters, or when selecting a pair of JFETs with the equal parameters for the differential stage. In this article, we will focus on the use of static parameters in the calculation of circuits based on JFETs.
Read MoreRefinement of the DEGEN DE1103 Radio Receiver: Applying the Signal from the Antenna Directly to the Input of the First Mixer
Wednesday , 4, July 2012 Radio, Solutions Leave a comment
The modification of the DEGEN DE1103 radio receiver described below was done to provide the radio receiving in long and medium wave bands with an external antenna (or with the standard telescopic antenna), but not with the built-in ferrite rod antenna. Now while working on short waves too, the received signal from the standard telescopic or an external antenna is applied directly to the input of the first mixer, bypassing the Q1 transistor stage.
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Using special soldering iron tips or a hot air gun to desolder surface mount chips in a TQFP package carries the risk of overheating the chip and / or printed circuit board. Below is a method for safely removing chips in a TQFP package – without overheating and with the ability to reinstall the desoldered chip. It does not require any special soldering equipment.
Read MoreMarch 1, 1941 can be considered the day of the appearance of FM radio broadcasting in its usual form, that is, as a commercial industry, when the W47NV radio station with a transmitting center in Nashville, Tennessee, USA, went on the air for the first time. Here is how the American weekly “Broadcasting” wrote about this on March 10, 1941 in the article “New FM Station of WSM, in Nashville, Starts Operation With 70 Hours Weekly”:
Attachment to Voltmeter for Measuring Static Parameters of JFETs
Monday , 4, July 2011 Measuring Leave a comment
To find out the parameters of JFETs, both n-channel and p-channel, the simple and inexpensive attachment to the voltmeter described below will help, which allows you to measure a zero-gate voltage drain current (IDSS) and a gate-to-source cutoff voltage (VGS(OFF)). Thus, using only this attachment with some kind of voltmeter, you can, for example, select JFETs with the best characteristics or select a pair of JFETs with the same parameters. In addition, the attachment allows you to check JFET for performance, to clear up the transconductance at the intended DC operating point, and for students and novice radio amateurs to examine the field effect transistor in order to better understand its principle of operation.
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