![]() ![]() ![]() I should have purchased a truckload of them when they were available! Similar capacitors with smaller values are still available if you look around. Unfortunately, Mouser no longer carries them, and I don’t know of another commercial source. The capacitors are poly film variable capacitors (2 sections 365pF each), which were originally purchased from Mouser Electronics. The extra input capacitance can sometimes be helpful on the lower frequencies. Using this switching arrangement, I can select between one section of the capacitor, both sections in parallel, or both sections in parallel with a fixed 470pF mica capacitor. How convenient!Īnother W6JJZ modification I used was the inclusion of a DPDT (center off) toggle switch to provide some flexibility with the input capacitor. Another reason for choosing the T-200-6 core was that I happened to have one in my junk box. Here again, I went with W6JJZ’s suggested turns count. The number of turns has to be adjusted for the Type-6 core, due to differences in permeability. W6JJZ recommends the Type-6 core over the Type-2 because it provides a higher Q over most of the HF range. ![]() First, instead of the T-200-2 toroid specified in the SPRAT article, I used a T-200-6 core. I incorporated a few modifications in my version, based on an article by W6JJZ (“The Z-Match: An Update”, QRP Quarterly, July 1995, pp 10-11). This design, by the way, is similar to the one used in the Emtech ZM-2. I based it on a classic design which was first appeared in SPRAT #84 (see the G3YCC web site for a schematic of the original design). I make no claims of originality for anything in my version of the Z-match. The range of impedances that can be matched is not as great as in other designs, such as the “T” configuration.Tuning is usually very narrow and can be a bit touchy sometimes.Here are some disadvantages of the Z-match design: This sort of thing usually appeals to QRPers. Using a toroid inductor and some small poly-film variable capacitors, the Z-match can be built into a very compact package.The fixed inductor simplifies construction (no taps or rollers needed).A well-designed Z-match tuner has a high Q and is more efficient (less lossy) than other types of tuners.Being a parallel resonant circuit, the Z-match can provide some band-pass filtering for your receiver and harmonic attenuation for your transmitter.Matches balanced loads without the use of lossy baluns.Why the popularity? Here are some advantages that the Z-match design offers: Emtech sold its wildly popular ZM-2 kit commercially and the NorCal QRP Club began selling their BLT tuner kit (a W6JJZ design) like hotcakes. Boasting impressive computer-generated special effects and eye-popping facial makeup, Taken was seen over a two-week period, beginning December 2, 2002, and ending on December 13.Z-Match tuners became very popular within the QRP community years back, thanks primarily to articles in QRP journals by Charlie Lofgren W6JJZ and the emergence of Z-Match tuners in kit form. The story was narrated by Allie Keys (Dakota Fanning), a "hybrid" child of the present day, whose story determined the outcome of the final episodes. And the lives of the Crawfords were dictated by ruthless Army officer Owen Crawford (Joel Gretsch), who was determined to prove that the government had covered up the truth about Roswell by dedicating his life to tracking down all space aliens and their half-human descendants. The Clarkes were originally represented by lonely Texas waitress Sally Clarke (Catherine Dent), who was impregnated by a charming stranger (Eric Close) who turned out to be an alien survivor of the Roswell crash. The Keys family was headed by WWII bomber pilot Russell Keys (Steve Burton), who spent virtually his entire adult life haunted by his "close encounter" with aliens. Covering a period from 1947 to the present, the story focused on three different families, each of whom was profoundly affected by extraterrestrial visitation. Executive-produced by Steven Spielberg, the ten-episode, 20-hour miniseries Taken was one of the most ambitious projects undertaken by cable TV's Sci-Fi Network, ultimately costing 40 million dollars - a price that proved well worth it, inasmuch as the series posted the network's highest-ever ratings. ![]()
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