Ham Radio . Magnum Experimentum
Antennas, experiments, engineering and other articles of interest to radio folks.
Tame the predictable mast currents found in any j-pole antenna grounding conductive mast using a simple stub. Shown is empirical evidence why this is a problem and a very simple solution all future grounded j-pole antennas should incorporate.
To function as intended, the J-Pole antenna needs RF electrical isolation from its mount. Here’s why and in technicolor no less.
Another 5/8 J-Pole Design arranged as a Collinear… can it justify the complexity and extra materials?
The Northern Virginia team of Ham Radio operators and companion hikers manned Hawksbill Mountain for the 2011 Appalachian Trail Golden Packet event. Gear included a Kenwood D710 with Green Light Lab GPS, 2m Collinear J-Pole and a 70cm collinear J-Pole.
Measurements and analysis suggest why quarter-wave stubs fail to completely isolate radiator conductors on multi-band antennas including the popular rollup 2m/440 J-Pole products. Possible improvements are shown.
Understanding why SlimJIM antenna aficionados hype the gain in their marketing and discussions.
You need an antenna with energy at high take off angles to hit the hill top repeaters… right? Well, not likely. Let’s review the details and do the math to understand what’s needed for VHF terrestrial radio communication.
One example of how amateur radio provides safety and service to the pubic providing otherwise impossible communications using the “Magic Band.”
My first journey to the mountains as SOTA activator was a success using minimalist VHF FM gear.
The traditional collinear J-Pole, aka Super-J, improves the basic J-Pole. Are further improvements possible? By replacing the phasing stub with a simple coil, the answer is yes. The result is the Collinear J-Pole.
Hiking, ham radio, hills and a portable collinear J-Pole combine to make the Golden Packet Test a memorable event.