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= = = "G.Beat" wrote in message
= = = news:UdtBc.152030$Ly.30888@attbi_s01... "Kees" wrote in message ... Hello fellow shortwave listeners ! More info to make a T2FD yourself, like I did mine, please have a look at: http://members.home.nl/rita.kees/t2fdmake.html I hope you can appreciate it and use it for your practice. I will be glad to answer your questions. 73/cheers Kees The Tilted Terminated Folded Dipole ("T2FD") is a broadband folded dipole antenna design that provides a relatively stable feed point impedance over about a five to one frequency range. The antenna length in meters is approximately 100 divided by the lowest desired operating frequency in megahertz. The upper element of the folded dipole is opened in the center and a non-inductive terminating resistor of around 350-400 ohms is inserted. The bottom element is fed in the center through a 6-to-1 balun for a good match to 50 ohm feed line. The antenna is not as efficient as a matched half wave dipole at any specific frequency, but it also does not require an antenna tuner for operation, making it easy to use. The loss of receiving efficiency is not generally noticeable in the high frequency range (2-30 MHz), amounting to less than 6 db (one standard S-unit) during extensive on-the-air testing. Here is additional information on the T2FD antenna. Barker & Williamson actually applied for a US patent (US Patent #4423423) for their specific T2FD antenna design. http://www.fact-index.com/t/t2/t2fd_antenna.html W9GB, B&W makes two general statements about the T2FD: * For example, an {T2FD} Antenna for the lower portion of Shortwave (3 - 18 MHz) will be roughly 33m (110 feet) long, with conductors spaced 1m (3.3 feet). [With a Top End mounted about 60 Feet High at 30 Degrees.] * In order to cover the higher portion of Shortwave (5 - 30 MHz), this {T2FD} Antenna will be roughly 20m (66 feet) long, with a spacing of 60 cm (24 inches). [With a Top End mounted about 40 Feet High at 30 Degrees.] Build one size or the other = No Formula Required. Read: T2FD Antenna - WOW ! ! ! {One SWL's Experiance} http://groups.yahoo.com/group/Shortw...na/message/293 iane ~ RHF .. .. While this may be acceptable for SWL operation, the resistor does not have sufficient wattage for any station attempting to use this for a transmitting antenna. http://www.tuberadio.com/tfd.html http://www.universal-radio.com/catalog/sw_ant/0562.html w9gb .. |
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