Using Tuned Passive Loop Antennashttp://www.dxing.info/equipment/passive_loop_antennas_schanilec.pdf
Using Tuned Passive Loop Antennas.
I’ve heard it said that successful Medium Wave DXing is 50% antenna and 50% receiver. In order to get the most out of the antenna factor, those with sufficient real estate will erect a EWE, Beverage, KAZ or other outdoor antenna. For those like me with little space or who have restrictive homeowners associations, one of the antennas of choice will likely be an indoor loop antenna. This might be a home-made box loop or a desktop ferrite loop such as the Quantum Loop. Those whose passion lies in using portable receivers, including the popular Ultralights, rely on the ferrite loop inside the receiver.
An often-overlooked asset is a tuned passive loop used to augment the primary loop antenna. A tuned passive loop is readily available commercially from manufacturers such as DXTools.com, Terk, Select-A-Tenna, and others. Alternately, one can be made quickly by the home hobbyist. This article is a summary of several techniques by which a tuned passive loop antenna can help DXers solve common problems.
Whether you are using a stock UltraLight or the Sony ICF-2010, judicious use of a passive loop (or two!) can make a huge difference. Additionally, for those like me who like to use a Quantum Loop or similar as the primary antenna for a communications receiver, all of these techniques are available. Optimum results are typically obtained when you employ the largest, most selective (highest Q) loop possible, your space and budget allowing. However, as described above, even an inexpensive commercial loop can be very effective. To find out more about loop design and construction, the document “Air Core Loop Designs” provides information on and links to a variety of different designs, and is available at the DXer.ca website in the Ultralight File Area. With all these tools in the toolbox, hopefully, one or two will work for you in a given situation.
Good DXing to you! Kevin S. Bainbridge Island, WA October 2008 satya(at)sounddsl.com