I agree with most of the statements about the TTFD, or B&W FD, if you prefer. While not as efficient as some, it meets a number of particular needs, especially that it has a similar directional pattern over a 5:1 frequency range -- especially useful for point-to-point links using multiple HF frequencies, either manually or by ALE.
I did an assessment of this antenna and wrote a QST article on it that I recommend for those interested. The one point I disagree with is the statement that the terminating resistor dissipates half the power. The power dissipated is a function of frequency and, while it is not far from 3 dB at the high end of the frequency range, it absorbs much more at the low end -- about 90%! Not only is that 10 dB less signal on transmit, but the resistor power rating needs to be 90% of the transmit output, if high duty-cycle modes are used. Note that it is not as big a problem on receive, since the receive S/N on the lower bands is sufficiently atmospheric noise limited, that the receive S/N is not greatly impacted, even though the s-meter will read lower by 10 dB. My article is available to ARRL members on the QST print archive on the ARRL website. Sep 2010 - QST (Pg. 51) A Close Look at the Terminated Folded Dipole Antenna Regards, Joel Hallas, W1ZR Westport, CT ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
