Vertical Antenna Theory: Loading and Ground Planes

Because of the sheer length of the radio waves in certain bands, portable antennas or antennas in low space/stealth applications use a number of tricks or compromises to get resonance and radiating power sufficient to make contacts. Two of these tricks and compromises used with vertical antennas are Loading and Ground Radials. Loading: Loading is …

Soda Can Battery From Trash

I really love DIY projects and proof of concepts with electricity and radio so when I saw this little project using soda cans, cardboard, copper wire, sand, and saltwater to build a battery, I was all over it. (video from rumble.com, an alternative to YouTube’s increasingly anti-free speech platform) Instructions: Cut the tops off of …

Soft-Start Circuit Design to Stop Inrush Currents

Some appliances or components like solar inverters can trigger circuit protection to kick in when they care first connected. The reason is that often they have large capacitors inside that can really spike current use while they are charging up on start-up. In the video below, the Great Scott YouTube user, an electrical engineer from …

DIY Portable Power Box Solar Charge Upgrade

Recently I finished building my first portable power box in an “ammo can”, and have been charging phones and testing radios with it. However… now it’s time to top the battery off, so I’m upgrading the box with a charge controller, and external port to plug in a solar panel. Here’s the video tutorial I’m …

Powerwall Battery Pack Construction with BMS

There’s a guy named Jehu Garcia in California who’s made it his mission to recycle laptop and other batteries in the United States instead of sending them back to China. One of his ongoing projects is building DIY power walls (similar to the commercial ones made by Tesla at a premium price) using these reclaimed …

Antenna Theory – UnUn Transformers for Impedance Matching

Baluns and UnUns come up frequently when discussing antennas of different types and matching feed point impedance so you don’t burn up the final stage transistors in your expensive radio. This video contains one of the best explanations I’ve seen so far of wave propagation in antennas, and how to build a transformer to convert …

Calculating Power Ratios from Decibels

Decibels have never really made a lot of sense to me, though I memorized the relevant numbers to pass both my Technician and General class ham radio operator license tests. I mean, 3dB = 2:1, 6dB = 3:1 and 10dB = 10:1? What sense does that make? And its bothered me that I didn’t know …