Applied Amateur Radio Technology
The 2M Ladder Line Antenna is similar to the J-Pole with increased RF energy at the horizon. I like it because it is easy to build and has a very wide 2:1 SWR bandwidth, about 6% (142-150 MHz). This antenna gives you about twice the gain as a standard J-Pole and two S-Units over a ¼ WL vertical when compared for point to point line of sight work. The antenna is impedance matched to the coaxial feedline by the stub. The coaxial shield is connected to short element and the coax center conductor is connected to long element. Best SWR is achieved by sliding the connection up and down.
Vector Antenna Analyzer for antenna testing with high quality data graphics and data file exports, sweeps, frequency plots, Smith charts, alerts and data file exports using a web browser on any OS / platform; MAC, PC, Linux, Android, tablet and even a cell phone. The key element is the analyzer controls and display are a simple website sever to communicate with any browser.
An Inline Power and VSWR meter is a valuable tool for the antenna builder and transmitter testing. I started this project as a bench meter to use when I was building a transmitter drive input. The idea to build an inline power meter came out of need rather than inspiration. The RF sensor is a Stockton bridge directional coupler, it turns the forward and reflected power into voltages that can be measured by an analog to digital coverter-CPU conversion into power levels.
BALUNs are a tricky business and difficult to understand but still easy for most to build. DIY construction of a Dual Core Guanella BALUN provides efficiency and common mode isolation when feeding balanced antennas from coax like dipoles or mismatch feeds.
5-element 70 cm QUAGI is constructed from 1/16" copper rod and 3/8" Plastic Rod is driven by loop for 50 Ohm feed match.
Anyone Remember Building Kits
Radio is a diverse hobby with many interesting aspects, using both old and new technology can be very rewarding; -- CW, SSB, digital modes, satellites, etc. Some Amateur Radio stations use high power transmitters to bounce signals off the moon reflecting back to earth. I enjoy being a minimalist to make contacts using tiny transmitters powered by a flashlight battery for international communications. I build HF, VHF and UHF antennas and operate in 90% digital modes from 1/10 to 10 Watts, QRP. I live in a deed restricted community so my information is based on my experience within the “no antenna” restrictions. My purpose is to share my projects and ideas with anyone who is interested. All amateur radio operators are welcome to share this information for your own experimentation with radio technology.