Tuesday, January 3, 2017

Simple Ham Radio Antennas--W5ALT Indoor Vertical Antenna. Post #1001.

W5ALT Indoor Vertical Antenna.
Author:  Walt (W5ALT).
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Accessed on 03 January 2017, 23:35 hrs, UTC.


Anyone who has operated from a small apartment or has been restricted by HOAs and CC&Rs will readily identify with Walt (W5ALT) and his attempts to use  amateur radio equipment in "stealth mode."

Walt's antenna is a loaded vertical that can be tuned to almost any HF amateur radio band. In this post, Walt says he's contacted over 100 countries, all fifty U.S. states on HF, and over 100 grid squares on 6 meters from his small apartment in Maracaibo, Venezuela.

Before Walt shows us how to build this small vertical antenna, he explains a few important considerations that apply to almost all vertical antennas, indoors or not.

Walt says verticals require a good ground radial system.  Since ground radials can occupy quite a bit of apartment space, he recommends using a balanced antenna or a few radials "to balance an unbalanced antenna such as a vertical."

Short antennas aren't very efficient, so you need a way to feed the antenna without having too many loses.

Be aware of RF dangers close to indoor vertical antennas.  Stay a few feet away from radiating elements and spend most of your time listening rather than transmitting.  Also, run low power if you can.

An effective indoor vertical antenna needn't be expensive.  Walt used common materials found around his apartment plus some inexpensive wire and coaxial cable to make his interior vertical. Walt adds that his cheap vertical does well, considering the cost.  "My antennas perform well and can be built from inexpensive materials."

Walt finishes his brief tutorial with some excellent photographs showing the finished product. His "bare-bones" vertical uses a base-loaded coil with two radial wires giving satisfactory coverage of all HF bands from 6 to 40 meters.

Walt adds this final observation:

"Well, without doing side-by-side comparisons, it's hard to really evaluate an antenna. All I can say is that it tunes on all the bands from 6 to 40 meters and I have worked the world. I am usually able to get through DX pileups, although I know my signal is not the best or strongest. The best indication of its perfomance is probably the QSL cards that I've received, some of which are shown on another page here. In the first 3 months using the vertical, I made over 300 contacts from about 50 countries. You decide if it works or not!
Walt W5ALT"

This sounds like an excellent project for a rainy afternoon!
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Aloha es 73 de Russ (KH6JRM)