Here’s your video introduction to Section 6.5, Specialized Antennas, in the ARRL General Class License Manual for ham radio. Watch this 16 minute video prior to studying the section, and you’ll be prepared to understand terms such as NVIS, log-periodic antennas, multi-band antennas, and the ever-elusive Beverage antenna. I recommend watching this video at 720p, the highest resolution available, as I do some drawing and the lines are pretty thin.
In the video I show a website that gives you near-real-time MUF propagation conditions for NVIS-type work. That website is www.spacew.com/www/fof2.html.
When you’ve finished, click here to return to the list of the videos.
Errata: In the introduction, “a couple you’ll see quite recently” should have been “a couple you’ll see quite frequently.” Also, I mention the May 2005 QST article. It was actually December 2005.
(Update, 20 Nov 2013: I received a question from Craig Mullins via Google+ about the efficiency of trapped antennas. Do they really work very well? If traps were perfect, no signal would be lost—each band would see only a dipole tuned to the right length. In practice, however, some energy is lost in the traps, though not very much. A trapped dipole is as good as any way to create a multi-band, resonant, low-SWR antenna. It has the great advantage that if it’s set up properly, no antenna tuner is required. It’s often a good choice for a ham getting started on HF, although I still say getting on 40 meters as a first band is a good choice.)