Saturday, June 9, 2012

Simple Antennas for the Amateur Radio Operator--a continuing series

HIDDEN ANTENNAS

Are restrictive covenants, limited space, and nosey neighbors ruining your amateur radio hobby?
There is no need to retire your amateur radio activities because of antenna issues.  With a little creativity, low power (QRP), and light gauge wire, you can enjoy amateur radio again.  While this "below the radar" or stealth operating technique can't rival the performance of a mono band beam on a tall tower, it can get you back on the air.  You might even have some fun and save money at the same time.

I'm always on the lookout for interesting antenna ideas, especially since my "antenna farm" is confined to a small backyard and faces close-in neighbors and high voltage lines.  Although I've used indoor antennas with some success, I prefer getting the rf outside if at all possible.

Today, I revisited a website maintained by Julian Moss, G4ILO.  Julian's well-designed blog provides a compact, easily understood tutorial on hidden and low visibility antennas.  He covers all the basic low visibility antennas in an easy to read, lively style.  The major types are here:  flagpole, invisible wire (long wire, inverted L), magnetic loop, short vertical diploe (the Transworld Adventurer), and loaded whip (screwdriver antennas and their variants).  Julian recommends these types of antennas rather than the Hamstick dipole, tripod mounted vertical, the Buddypole type of antennas, and the slinky dipole.  These later types, he says, are inefficient.  Julian also provides basic information on attic mounted antennas such as loops and shortened dipoles.

I've found several of Julian's ideas useful in my operating situation.  He could help you, too.  For details, visit http://www.g4ilo/com/stealth.html.

As for my own antenna situation, I feel comfortable with what I'm using.  Most of my 20 meter activity is fed to a vertical dipole in the back yard.  I feed the dipole with either RG-6 (for 20 meters only) or 450-ohn balanced line (20 to 10 meters).  Along the side of the house, I have an "upper and outer" antenna (33-foot vertical on a fiberglass pole with a 33-foot counterpoise) fed with 450-ohm balanced line.  That antenna can work from 40 to 10 meters with a suitable balun and my trusty Drake MN-4.  The design of this antenna goes back to the 1920s and 1930s and was popularized by the late Lew McCoy (W1ICP).  Speaking of McCoy, CQ Communications, Inc. still offers his outstanding book "Lew McCoy On Antennas.  Pull Up A Chair and Learn From The Master." 

The rest of the day will be spent paging through McCoy's book, reassembling the Drake MN-4 (after a thorough cleaning), and cleaning all contacts and switches in the venerable Swan 100MX I use for ragchewing.

I hope your weekend will be one filled with dx and other interesting radio adventures.

Aloha es 73 de KH6JRM--BK29jx15