Ham Radio . Magnum Experimentum
Antennas, experiments, engineering and other articles of interest to radio folks.
Simulations and testing are shown in these articles about ham radio, and a few other, antennas.
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.
Basic tests of the LNR Precision EF-10/20/40 multi-band portable HF EFHW antenna including S11, SWR and a bandwidth check of the match box.
The background and details of the LNR (Par Electronics) EF-10/20/40 end fed half-wave multi-band portable HF antenna. Come see what’s inside the mysterious “black box.”
To function as intended, the J-Pole antenna needs RF electrical isolation from its mount. Here’s why and in technicolor no less.
My G3TXQ Hexbeam gets a new metal backbone to accommodate a VHF beam antenna. A byproduct is a much stronger antenna assembly than the common Hexbeam approach.
My 43 foot vertical took a beating last night in the Canadian cold air clipper and lost its lower U-Bolt.
So what do the Dallas Cowboys, Digital Television over the air broadcasts, my wife and the Hex Beam have in common…
You’re probably thinking…
“Man… John has lost it. He’s blogged one post too far… On Halloween afternoon too…”
Hang with me for a moment.
The MFJ Analyzer products make easy work of tuning a coaxial quarter wave stub.
Two NMO through-hole antenna mount parts, the Laird MBO and MABO, were prototyped to help down select the choice of 3/8″ or 3/4″ hole. The opinions of engineers, machinists and others were obtained.
It’s time to replace my mag mount antenna and go “through hole” with my Mobile Antenna. NMO seems to be the way to go. Reviewed are some candidates from brand name to no name.
“Shocking” evidence our aerials collect electric charge plus an educational video on the topic of static electricity.
Magnetic Mount Antennas get a bum wrap it seems and for poor reasons and misunderstanding on how antennas work. Here is a way to see they are not so bad afterall… at least electrically.
Test results of the Coaxial Cable Balun and the Folded Balun (aka Pawsey Stub) reveal coax Velocity Factor applies to the former, but not the latter, unlike what many web sites would have you believe. Part 2 of 2.
Test results show coaxial cable velocity factor does not always enter into stub length calculations especially in the world of Baluns. Part 1 of 2.
FDTD reveals Hex Beam behavior with real movies of magnetic and electric fields in time.
By now I have posted several times about my new G3TXQ Broadband Hex Beam which came online in March 2010. I figure it is time to post a bit more on the materials I used for my version of the hex beam. Read more about the fine spreader kit from Max-Gain Systems.
The Field Day Broadband G3TXQ Hex Beam works Hawaii from Virginia during Field Day.
In the never ending quest to improve our HF mobile ops for the Virginia QSO Party we finally decided to try a small loop.
There is nothing new about small loop antennas. They have been discussed in the literature for decades. The ARRL has some very old articles about them in the 1968 March and July editions.
Constantine A. Balanis’ book on Antenna Theory discusses and defines large vs. small loops. This book is an essential reference if you seek the details on how loops work. The loop described below fits into the “small loop” category where the currents along the conductor are, for all practical purposes, constant. This is unlike full size antennas where current reaches a minimum where voltage approaches maximum. Since this loop is electrically short with respect to wavelength, current does not change “much.”
The new antenna for 2010 at this QTH will be the popular G3TXQ Broadbeam Hex Beam. What follows is a look at the DX Engineering Hex Hub.
Can the 10-20 meter five band HF G3TXQ broadband hex beam be used on 6 meters as is?
Which full-wave loop to try first: 40 meter, 80 meter, 160 meter, more?
Photo album showcasing the creation of a home made ladder transmission line.
Keep it simple for the Jamboree on the Air – Use a ladder line fed dipole.
Here are some details regarding the next, and probably last, phase of my 43 Foot DX Engineering vertical installation.
This post is very late. The actual date of the events within it are just before March 2009 in preparation for the Virginia QSO Party.
In the many posts within this site, it is no secret my examination of various vertical antenna solutions with comparison between BigIR and the 43 Foot products a big part of this. Check out all the 43 Foot posts on HHD here…