Wednesday, June 13, 2012

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

WHEN DOUBT, IMPROVISE!

During a recent read of the articles posted on eham.net, I came across an interesting antenna story by Dale Kubicheck, N6JSX (12 June 2012).  The article entitled "HF 18VT Vertical Fence Mounted With an Ugly-Balun" caught my eye because of the way this ham recovered, rejuvinated, and restored an old vertical antenna to its former glory.  This article contains a series of pictures and descriptions of the creative process leading to a semi-homebrew antenna that really works.  Once Dale rewound a few coils, cleared the corrosion from the antenna sections, and fashioned a new balun, he attached the antenna to a chain link fence, which formed part of his counterpoise system.  Although he may need some radials in the future, the antenna apparently delivers the results Dale wanted.  Dale's pictures and explanation are excellent.

Eventhough you may not have the tools Dale uses, you can still make a good antenna with what you have on hand.  Even an old 108" CB whip can be modified to perform well on 10 meters.  Check out the ads for the Solarcon A-99 vertical, which is only a modified CB antenna.  Many amateurs have used this antenna with a decent radial field or counterpoise system to work stations from 20 meters to 10 meters.

I once lived in a house that had a wooden fence surrounding most of the yard.  I used the 5' high fence to support a 40-meter loop.  The antenna was nearly invisible unless you looked closely at the fence.  This antenna worked all bands from 40 meters to 10 meters when I fed it with 450-ohm balanced line, balun, and a tuner.  Although most of the radiation went straight up, I managed to snag many DX contacts.  The antenna was great for NVIS applications, such as local rag chew and emergency nets.  I have a 40-meter loop under my house for that very purpose.  The loop also works as a great MF and SW antenna for my Hallicrafters SX-62A.

So, let your creativity loose.  Use what you have on hand or can buy locally.  Your local hardware or building supply store can provide you with all kinds of things--wire, pvc poles, connectors, tools, etc.  Also, don't be afraid to ask your local cable company for any unused lengths of RG-6 coax.  You might get lucky and stumble upon 50 or more feet of this cable.  I've used RG-6 for patch cords and antenna feed lines.  The slight mismatch of this cable (75 versus 50 ohms) can be handled by most antenna tuners.  A careful search through various on-line catalogs can help you find suitable connectors which will enable you to convert the type F connectors to UHF connectors for your rig.

You are only limited by your imagination.

Have an excellent day!

Aloha es 73 de KH6JRM--BK29jx15