Mentor’s Corner

Many of our members have been licensed and active hams for many years and have technical backgrounds and lots of experience. If you have questions about ham radio (or related tech), someone can likely help you out.

We regularly publish mentoring responses and other technical bits of interest here.

  • Opto-Isolators: A Very Useful Device in the Ham Radio World
    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 the input and output is also very small.  They are commonly found in radio interfaces where you want isolation between your radio and your computer.  The audio is commonly isolated with transformers and the PTT…
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  • Using Nano VNAs – Component Measurement
    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 and capacitors to see if their markings agree with the NanoVNA display. In the boat-anchor days, Heath had an Impedance Bridge kit. I built one in high school. Conceptually, it was a simple instrument containing…
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  • My Path Back To Ham Radio
    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.  Upon the advice of my doctor daughter, I went to the Plano Heart Hospital ER.  When I walked in the door and explained my symptoms, things started happening fast. Tests and an X-ray confirmed I…
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  • Using Nano VNAs – Band-Pass & Band-Stop Filters
    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 called notch) filters. Below are the filter use instructions from my Yaesu Ftdx-3000 manual. As you can see, the band-pass filter on the left can be adjusted to move the IF passband up or down…
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  • Using Nano VNAs – Low-Pass & High-Pass Filters
    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 for about 12 bucks.   This device contains a lot of test components that you can experiment with while exploring the functions of your Nano VNA.  Note the 30 MHz low-pass filter (LPF ) and the…
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  • Using Nano VNAs – Antennas
    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 watch the video replay of the October 2021 RWK program by Alan Wolke W2AEW. Alan covers a lot of basic information so I won’t repeat anything in his excellent presentation. In the next few issues of…
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  • Antenna Modelling Software for Ham Antennas
    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 to perform complex calculations by hand to estimate the performance of even simple antennas, but now with the advent of computer modelling software, the average ham can create a fairly complex computer model of simple…
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  • FCC RF Exposure Rule Change
    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 had been exempt from having to perform an RF Exposure evaluation on Amateur Radio stations and equipment. The December 2019 Report & Order eleimnated that catagorical exemption for the Amateur Service and adopted a 2…
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  • Solar Propagation – What You Need To Know
    By Jon Suehiro NN5T You see this image on RWK home page – . 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? This graphic is updated several times a day and contains the latest relevant data and statistics that are relevant to ham radio propagation. Ideally, you should be able to look at this and get a…
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  • Transmission Lines and Wave Behavior
    Here are a couple of informative and entertaining videos on transmission lines and wave behavior. — Courtesy of Michael WT9V
  • Stealth Vertical Antenna Idea
    by Mike Jahrig KG5P – Hams living in HOAs are always trying to figure out what kind of antenna they should use so they won’t get caught violating the covenant agreements. I hear all kinds of solutions from flagpole antennas to using old corroded rain gutters. Here is an idea I came across. It as stealthy as you can get and still be an antenna. In addition, I can think of no reason that…
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  • Impedance Matching
    (Or Stuff that Every Ham Should Know) by Mike Jahrig KG5P – I had a discussion with a fellow ham recently. He has a nice modern rig but was unclear why the antenna impedance and feedline characteristic impedance must be matched to the transmitter impedance (almost always 50 ohms) Since this is something that every ham should or must know, I believe it is important that I mention it. My fellow ham thought that…
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Beau’s Korner

Beau Williamson N5PY

Beau Williamson N5PY (SK) was a dedicated and involved member of the RWK and the North Texas ham community, serving as Director of Mentoring and Education for RWK until very recently. In that capacity he helped many hams learn and sharpen their CW skills, earn license upgrades, and generally improve their overall technical knowledge. Beau was honored for this work with a special award at the RWK President’s Dinner on January 12, 2020.

In honor of Beau’s long service to the club, the pre-meeting gathering of Mentors at the RWK General Meeting has been named “Beau’s Korner”. This group is available to answer questions and opine on all things ham radio for any newly-licensed hams or anyone else that needs help of a primarily technical nature.

November 2019

October 2019