Richardson Texas – Club Call K5RWK
By John Slaughter WB5HSI An opto-isolator is a light emitting diode and a phototransistor in the same package. The LED is completely isolated electrically from the phototransistor. Most devices have 1000 volts or more of isolation. The capacitive coupling between…
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By Mike Jahrig KG5P (Part 4 of a series) Last month we discussed four types of filters and investigated their behavior using the NanoVNA. This month we will use the Nano to identify the values of some junk box inductors…
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by Brian Murphy WB8QZM On a typical hot August day in 2020, I found my path back to ham radio. I was used to cycling 20 miles a day but for the last two, had experienced unusual shortness of breath. …
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By Mike Jahrig KG5P (Part 3 of a series) Last time we discussed investigating the properties of low pass and high pass filters using the Nanovna. Today we will discuss 2 additional common filter types, the bandpass, and bandstop (sometimes…
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By Mike Jahrig KG5P (Part 2 of a series) This month I will continue my discussion of the NanoVNA. One useful accessory I have found is a RF Demo Kit that I bought off the internet from Banggood or somewhere…
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By Mike Jahrig KG5P A lot of RWK hams have purchased NanoVNAs. I recently obtained myself, and have learned that it provides a wealth of information in the shack. If you are not familiar with this device I suggest you…
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By Chip Coker KD4C Have you always thought that antennas were “magic”? Well hopefully you understand that there is actual physics involved in the way antennas work, even if it’s not obvious to us. In the past, RF engineers had…
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By Chip Coker KD4C By now, you may have seen or heard that the FCC published a change to their regulations in December 2019 that changes the Rules on RF Exposure evaluations. In short, in the past the Amateur Service…
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By Jon Suehiro NN5T You see this image on RWK home page – https://www.k5rwk.org/ . But what does it mean? You also hear about Solar Cycle 25. What do you need to know about the current propagation and solar conditions?…
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Here are a couple of informative and entertaining videos on transmission lines and wave behavior. — Courtesy of Michael WT9V