Of end-feds and feed-lines
Simulations suggest end-fed and center-fed half-wave dipoles share sensitivity to various feedline lengths, but in differing and manageable ways.
NEC
Simulating the end-fed half-wave (EFHW) dipole antenna
A NEC model that includes the transformer helix helps demystify the end-fed half-wave (EFHW) dipole antenna using the autotransformer as impedance converter.
Antenna radiator decoupling stub flub?
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.
SlimJIM and Antenna Gainflation
Understanding why SlimJIM antenna aficionados hype the gain in their marketing and discussions.
Slim Jim vs. Traditional J-pole Antenna
Real measurements of a Slim Jim antenna and traditional j-pole antenna reveal the truth about their respective gain and pattern.
NVIS Gain of Loop and Dipole vs. Height
Observations from the Virginia QSO Party confirm simulation results concerning horizontal antennas and NVIS propagation.
Have your J-Pole and ground it too
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.
HF AHVD on 6m – Practical?
Will the KX4O version of the 20-10m Asymmetrical Hatted Vertical Dipole work on 6m? Yes, sort of.
Build this Vertical Portable HF Antenna
The Asymmetrical Hatted Vertical Dipole (AHVD) prototype is an easy to build, portable alternative to other freestanding vertical HF antennas such as the Buddipole.
Asy Hat Vertical Dipole
We re-introduce the theory and origins of Cebik’s (W4RNL) Asymmetrical Hatted Vertical Dipole (AHVD) antenna with the hope to facilitate a vertical polarization portable 20-10m aerial for portable operations.
40m Mastless NVIS Antenna
Yet another 40m Cloud Burner design featuring a folded dipole driven element plus one reflector wire to facilitate 40m NVIS contacts without need of a tall mast. The design uses electric fence posts for support and needs no balun.
Wideband 80m Dipole
A 1/4 wavelength of 75 ohm coax inline with a full wavelength of 50 ohm coax is all one needs to make a simple 80m dipole become a wideband dipole antenna.
Superbowl HDTV Antenna
Build the venerable Hoverman TV antenna and watch digital broadcast high definition HDTV television this weekend. This version of a HDTV antenna uses amateur radio antenna building techniques to make a lightweight structure.
Copper 6m Coplanar LFA Yagi-Uda
The Coplanar Loop Fed Array (LFA) Yagi-Uda design from G0KSC provides an excellent design foundation for an all copper version of a 3 element 6m balunless beam with superior front to back performance. Shown are comparisons between model simulations and prototype measurements.
Coplanar Loop Fed Array LFA Yagi-Uda Antenna
The clever application of the folded dipole loop, computer science iteration techniques and NEC simulation to Yagi-Uda design results in a panoply of practical planar Loop Fed Array, LFA Yagi antenna recipes.
Improving the Super-J
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.
EFHW LNR Precision EF-10/20/40MKII Examination
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.”
Antenna Measurements on Taurus 2m Whip
Return Loss and SWR measurements of a permanent 2m whip installation mid-roof of a Ford Taurus. The effect of doors is shown.
5 HF Band Hex Beam on Six Meters
Can the 10-20 meter five band HF G3TXQ broadband hex beam be used on 6 meters as is?
Hiking, Hams and Hills – Station #6 of the AT Golden Packet
Hiking, ham radio, hills and a portable collinear J-Pole combine to make the Golden Packet Test a memorable event.
Collinear 5/8 wave J-Pole vs. Collinear 1/2 wave J-Pole EZNEC Shootout
Another 5/8 J-Pole Design arranged as a Collinear… can it justify the complexity and extra materials?
NVIS 80m with 160m Full Wave Loop is less than ideal
Big HF loop antennas provide great performance, but they can’t do everything. 160 meter full wave loops won’t work well for NVIS when used at 3.8 MHz.