In “The W4SSY Spudgun” [Mar 2009. pp 67-69], Byron Black, W4SSY, reports that he has been informed that OSHA recommends against use of PVC for above ground compressed air. The problem, per James R Divine, PhD, PE, WB7DJX, is not so much that the PVC can fail as that if it does fail, it shatters, resulting in a hazard to everyone around. Further, as the temperature drops, it becomes more and more brittle, and thus should not be used in cold weather. In any case, the area should be kept well clear. Wrapping the air chamber with reinforced duct tape may help, but it is not a proven technique. The author has supplied supplemental information that can be found on the QST binaries Web site at www.arrl.org/files/qst-binaries/.
In “Announcement — Second ARRL Homebrew Challenge,” [Feb 2009, p 75], the caution about a “beryllium substrate…” should have said “beryllium oxide substrate….” Check the new Homebrew Challenge Web site at www.arrl.org/qst/hbc/ for rules clarifications and reader questions and answers.
In “Product Review — TelePost LP-PAN Software Defined IQ Panadapter,” [Feb 2009, pp 44-50], it was stated that mono to stereo adapters for the output connectors were not available from RadioShack. Brian Torr, N6IIY, noticed that RadioShack sells what they call an “Aircraft 2” adapter that converts a 1/8" stereo jack to two 1/8" mono plugs. It is RadioShack part number 42-2495. They also sell a Y adapter to convert an 1/8" stereo jack, such as on the laptop’s sound card, to two 1/8" mono jacks, part number 274-375.
In “The World Above 50 MHz” [Jan 2009, pp 87-89] the Internet address for the Summitek Instruments company document on “Passive Intermodulation Measurement Techniques” was incorrect. The correct Web address is www.summitekinstruments.com/passive/docs/pimprimer.pdf.
The author’s footnote references were inadvertently left out of “A Lost Dit of Vibroplex History” [Feb 2009, pp 58-59]. The footnotes and the text that they reference are as follows:
• Horace G. Martin invented the Autoplex and the Vibroplex in New York City in the early years of the 20th Century, but the first Vibroplex manufacturing plant was located in, of all places, the little town of Norcross, Georgia. [J. Ceccherelli, “Vibroplex — The Company and its Classic Key,” QST, Jan 2003, p 48]
• William R. Holly, K1GH, adds some detail on the Norcross connection in his definitive history of the Vibroplex Corporation. [W. R. Holly, The Vibroplex Co., Inc. 1890 to 1990, The Vibroplex Co, Inc, 1990]
• According to published reports, young Buck Buchanan learned telegraphy from a depot operator by the name of Dave Wall. [“Edward F. Buchanan,” The Atlanta Georgian and News, Dec 6, 1910]
• As is well-known, Martin became highly proficient, a world-class operator. [J. Casale, Ed., “Horace G. Martin, Part One: The Telegrapher,” The Old Timer’s Bulletin, Nov 2002]
• It would be tempting to conjecture that Martin and Buchanan became acquainted when both worked as telegraphers in 1904 in New York City. [Holly, p 5]
• The partners of the firm, including Edward F. Buchanan, whom The New York Times described as “the young Napoleon whose strategy had failed to connect” even spent some time under arrest. [The New York Times, Aug 26, 1908]
• The Horatio Alger kid found himself back at the Atlanta Western Union office where he applied for a job saying, “Just make me a plain old op.” [“Edward F. Buchanan,” The Atlanta Georgian and News, Dec 6, 1910]