The J-Pole antenna is herewith fixed
For what it’s worth, the myths surrounding the J antenna have been sorted out resulting in an improved version.
Ham Radio . Magnum Experimentum
Antennas, experiments, engineering and other articles of interest to radio folks.
For what it’s worth, the myths surrounding the J antenna have been sorted out resulting in an improved version.
Measurements reveal the effects of common mode current on the J antenna.
Real measurements of a Slim Jim antenna and traditional j-pole antenna reveal the truth about their respective gain and pattern.
The J-Pole antenna’s long and storied design history is due for one more chapter to mitigate the longstanding mast current and reliability issues.
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.
We examine if 5/8 Wave J-Poles are better than 1/2 Wave J-Poles.
Another 5/8 J-Pole Design arranged as a Collinear… can it justify the complexity and extra materials?
Analysis to suggest you really can use a 2 meter J-Pole in the 70cm band.
Myths abound concerning how J-Poles do so well. Here is an EZNEC shootout between a 2 meter J-Pole and a Monopole with radials.
Can a 2 meter J-Pole antenna work well on a child’s playset? Read and find out.
Review of the smallest portable 2m antenna on the market producing full size dipole performance and stows into your pocket.
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.
Tests suggest transmission line decoupling stubs are not immune to the conductor past the stub.
Does one really need to upgrade the antenna that came with your HT? Presented are EIRP measurements of various aftermarket HT aerials to help understand the trade space.
There are many ways to morph the basic J antenna into useful forms.
USD798847S1 showcases one more incremental step towards a J antenna that works with masts and feedlines.
The “mast mountable antenna” patent application is now available to review and critique.
In the 21st century should we believe antenna graphical gain data based on hope and hearsay? J-pole antenna gain drawings are a common bad example.
Understanding why SlimJIM antenna aficionados hype the gain in their marketing and discussions.
G4CQM provides details on a Yagi-Uda coaxial dipole driver approach for designers lusting after a 50 ohm self-balancing feed.
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.