Doing a little hammy ham ham research during the solar eclipse at the Ole Farm-O-La…Welcome to the first Technical Bulletin of the KM1NDY – Secret Amateur Radio Journal. Hull 2024 Effect of solar eclipse on WSPR transmissionsDownload ..read more

Every now and then I decide it’s time to homebrew a receiver. You may remember my attempt back here. Or even way back here. They never work. So this even more complicated, 3 transistor, 2 diodes, and audio amplifier IC definitely did not work. Again. Well sort of. Technically it is actually a receiver. Just not what I was hoping for. See the electrolytic capacitor I am pointing out down below? And the resistor that is in series with it? If I touch either with my fingertip, while the circuit is live, radio stations play through the loudspeaker. These components form a loop from pin 8 to pin 1 o ..read more

Stole the OM’s radio, grabbed the puppy, and went to make a qso or two for the CQWW SSB contest down on the seawall at Castle Island. That is the Elecraft KX2 with the AX1 antenna. I only managed a single contact…but it was to Slovenia. I think it counts. KM1NDY ..read more

The mark of an expert is knowing not simply what you know, but knowing what you don’t know. There are things in life I am truly an expert in. Electricity is decidedly not one of those things. For every new tidbit I learn, a door opens to reveal a seemingly infinite number of topics I haven’t scratched the surface of or even realized existed. In essence, I really don’t know what I don’t know when it comes to electronics. My last blog post was evidence of this. The nuts and bolts of the previous post was that my Koolertron 60MHz Function Generator was not outputting a stable voltage (amplitude ..read more

How hard could it be to construct a little band pass filter, throw a signal through it, and see if it properly attenuates? A breadboard, a small handful of components, an online filter design tool. Fifteen minutes, tops? I was longing for the pleasurable jolt of satisfaction that one only gets by watching an illuminated wavy line grow and shrink. I found the Marki Microwave LC filter design tool, chose a 2nd order Butterworth bandpass filter design, and centered it around the 40M ham band (7.1MHz or so). Hopefully they don’t mind that I cut and pasted the results of their lovely tool below. I ..read more

I would be absolutely lying if I told you that the polar coordinate functions of my beloved TI-84 Plus CE calculator were anything less than horribly annoying. Like a lot of math, and math calculators, there are roughly 3312 (that’s considered the “KM1NDY number”,i.e., K#, for those learning the most avant garde methods of mathematics) different ways to solve vector calculations. I just want one good one. I want to plug in a polar coordinate into my calculator add some math function (+, -, *, / , you know the drill…), plug in another polar coordinate, and get a result. Or, even better yet, mix ..read more

Sending out a flurry of sinusoidal waves to those important people who share this lovely day with me! Love you guys ..read more

Solidly in the back nine now ..read more

Along my journey on understanding radio, electronics, and in particular, the magic of baluns, ununs, and other transformers, I came across this helpful video on how to analyze a 49:1 unun with a NanoVNA. I replicated it with the the “Alleyway Antenna” transformer. This one below…unfortunately I did not take a lot of pictures of the build. I calibrated the nanoVNA with coax jumpers in place. I set up the NanoNVA like this: S11 port to input coax connector of unun 3.2 kΩ nominal resistance (3.272 2Ω measured resistance) in series with the unun antenna port and the S21 port of the nanoVNA. NOTE ..read more

These are the written steps and code necessary to upload C programs to an Arduino Uno through the Linux terminal without needing to use the Arduino IDE. I am most certainly NOT the originator of this, and proper credit goes to the “Low Level Learning” Youtube channel, and specifically this video entitled “Getting Started with Baremetal Arduino C Programming | No IDE Required [Linux SDK]”. This methodology is entirely reproducible, as evidenced by my blinking Arduino taking up space on the TV tray in front of me. 1. Connect your Arduino to a usb port in your Linux machine. 2. I recommend testi ..read more