What is characteristic impedance?
The RF world is full of esoteric terminology, and not least of these is characteristic impedance, or Z0. Most coaxial cables have a characteristic impedance of 50 or 75 ohms. If you want to...
QUCS for Filter Design
Introduction QUCS, or Quite Universal Circuit Simulator, is a freeware utility that allows you to draw circuit schematics, and perform AC & DC simulation, noise simulation (for S-parameters, and AC simulations), S-parameter simulation, and...
DMR – Digital Mobile Radio
DMR has taken off in our local ham club, and around the world. If you just want someone to talk to, there is always someone out there, somewhere around the world. If this is...
My IC-7300 TX Audio Setup
The IC-7300 has very good transmit audio out of the box, with the stock microphone. With a little tailoring to your voice tone, it can give excellent results. It seems though, I’m never happy...
Radioddity GD-77: A look inside
After many people telling me that my blank screen issue is down to a loose ribbon cable, and since Radioddity are replacing my defective GD-77, I saw no harm in having a look inside....
Radioddity GD-77 Blank Screen
I recently bought a Radioddity GD-77 DMR handheld radio. Initially, I was very happy with the performance, if a little quirky. Its quirkiness inspired me to write a post about how to set it...
Antenna Tuners, Impedance Matching, and SWR
Antenna tuners seem to be some of the most misunderstood devices in all of amateur radio. In this article, I’ll try to explain what is happening when you use an antenna tuner. I’ll try...
PL-259 Soldering
Do you solder the coaxial shield to the connector body when installing a PL-259 plug? What are those holes really for? I’ve been installing PL-259 plugs onto coaxial cable since I was about 16,...
Radioddity GD-77 Setup
Introduction I bought one of these on an Amazon Deal for about $64. I started to wonder if it was actually such a good deal after fighting with it for a while. It’s pretty...
Ham radio causing USB disconnect
For a while now, whenever I’ve had my PC on, and I’ve been talking on SSB (several bands), I hear occasional Windows USB connect/disconnect sounds. Generally a disconnect sound whenever I start talking, and...