Tue, 31 Aug 2021

Short-wave antennas

— SjG @ 11:00 am

English is a weird language. Insects, have two things called “antenna” sticking out of their heads and the plural is “antennae.” A radio tower, which is an antenna, is pluralized “antennas.”

Anyway, according to Los Angeles County, California – Code of Ordinances Title 22 – Planning and Zoning Division 7, section 22.140.040 – Amateur Radio Antennas, pending a Ministerial Site Plan Review, we could set up our antenna for 75 ft tower/mast, just so long as it is lowered to 35 ft total height when not in use. There are also rules preventing towers from being on the “street side” of the house, or in the front 40% of the lot. Some of these rules have carve-outs for civil defense or emergency responder applications, as well as for proximity to power lines, which could be relevant with the poles along the back of our lot.

Companies like HyGain make a great “crank-up” towers that are suitable for residential like this example setup for 14 MHz, 21 MHz, and 28 MHz HF operation. Likewise, the Aluma T-75HN extends to 75 feet but cranks down to 25 ft when not in use.

In the event of major disasters, having short-wave communication capability could be vital in helping coordinate rescue and incident operations (obviously, having backup power for the system is going to be an important component too).

A wide-angle lens adds distortion that makes it hard to pre-visualize, but here’s a possible perspective view. Specific antenna details would vary depending on the bands we opt to use.

Perspective view
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