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QEX: The July/August 2012 Issue

07/09/2012

The July/August issue of QEX -- the ARRL’s “Forum for Communications Experimenters” -- is coming soon, and it is full of theoretical and practical technical articles that you won’t want to miss. Published bimonthly, it features technical articles, columns and other items of interest to radio amateurs and communications professionals. The mission of QEX is threefold: To provide a medium for the exchange of ideas and information among Amateur Radio experimenters; to document advanced technical work in the Amateur Radio field, and to support efforts to advance the state of the Amateur Radio art.

Here’s what you’ll find in the July/August issue:

  • George Works, KJ6VW, and Shelley Works, KG4SRS, describe the extensive experiments they undertook while looking for “Confirmation Measurements of Vector Potential Waves.” In an effort to duplicate the experiments Bob Zimmerman, NP4B, reported on in the July/August 2011 issue of QEX, they confirmed that the plasma tube does detect signals, but they may have an explanation that does not involve vector potential waves.
  • Glenn Elmore, N6GN, introduces a different way to think about how an antenna radiates signals in “A New Antenna Model.” In the May/June 2012 issue, we learned about surface wave transmission lines (SWTL). Now Elmore describes a way of looking at an antenna as a SWTL, providing an impedance match between the 50 ohm feed line and the 377 ohm impedance of free space. This can help us visualize radio waves travelling along a dipole elements, and then radiating off the antenna.
  • Sivan Toledo, 4X6IZ, describes the “High Performance Sound-Card AX.25 Modem” that he developed. Toledo describes some common problems that AX.25 software modems exhibit, and explains how his modem solves those problems. The software modem is available for download from the ARRL QEX files website.
  • Dr Christopher Kunze, DK6ED, has used 80 and 160 meter Beverage antennas. The length of such receiving antennas is a deterrent to many Amateur Radio operators who might benefit from the low-noise characteristics of these antennas. Kunze has some suggestions for solving that problem in “New Results on Shortening Beverage Antennas.”
  • Steve Whiteside, N2PON, describes the design and construction of “A Linear Scale Milliohm Meter.” This dedicated low-resistance measuring instrument can simplify many troubleshooting tasks. The author describes several ways the meter will come in handy around just about any ham shack.

QEX is edited by Larry Wolfgang, WR1B, and is published bimonthly. The subscription rate (6 issues) for ARRL members in the US is $24. For First Class US delivery, it’s $37; in Canada and internationally by airmail it’s $31. Nonmembers add $12 to these rates. Subscribe to QEX today.

Would you like to write for QEX? It pays $50 per printed page. Get more information and an Author’s Guide here. If you prefer postal mail, send a business-size self-addressed, stamped envelope to QEX Author’s Guide, c/o Maty Weinberg, ARRL, 225 Main St, Newington, CT 06111-1494.



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