SlimJIM and Antenna Gainflation

E-plane gain plots of J antenna variations

Understanding why SlimJIM antenna aficionados hype the gain in their marketing and discussions.

Slim Jim vs. Traditional J-pole Antenna

Measured gain of SlimJIM and J-Pole

Real measurements of a Slim Jim antenna and traditional j-pole antenna reveal the truth about their respective gain and pattern.

Have your J-Pole and ground it too

1.06 GHz Test J-Pole Antenna

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.

Diamond X50 Antenna Measurements

Diamond X50 SWR and Return Loss

I measured the SWR and Return Loss of a loaner Diamond X50 antenna.

Hoverman TV Antenna Measurements

Hoverman VHF Elevation Measured Antenna Pattern

Doyt Hoverman’s 1960s TV antenna design placed over a simple reflector screen provides impressive performance for today’s UHF and VHF-HI television bands.

HF AHVD on 6m – Practical?

Tall 6m AHVD making local contacts.

Will the KX4O version of the 20-10m Asymmetrical Hatted Vertical Dipole work on 6m? Yes, sort of.

Build this Vertical Portable HF Antenna

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.

40m Mastless NVIS Antenna

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.

Superbowl HDTV 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.

SWR of Several Mobile Antennas

SWR of Several Mobile Antennas

I had occasion to test four popular amateur radio mobile antennas. Here are the results of SWR and Return Loss of a Diamond SG7900ANMO, Larsen NMO 2/70, Cushcraft CS-270M and Laird QW144.