T2FD is short form for Tilted Terminated Folded Dipole, also known as Balanced Termination Folded Dipole antenna and Broad Band Terminated Dipole. At the outset let me thank @SM0AOM for introducing the concept to me. It can perform as a broad band antenna for almost the whole of the HF spectrum up to 30 MHz. But it is a compromise antenna with gain much lower than a resonant dipole antenna on the lower bands. Would like to know from homebrewers out there about the versions which you have homebrewed and used. I am thinking of homebrewing one because I have space limitation and still want to try out lower bands.
If someone with space restrictions wants to use a T2FD on the "low bands" the results will be quite disappointing. When the overall length drops below 1/3 wavelength the efficiency drops dramatically, and the previously mentioned SM6APQ(SK) who had made extensive experimentation with the T2FD when working for the UN in Africa and the Middle East was of the opinion that 2/3 wl overall was the preferred length for "reasonable" performance at 3.5 MHz.
Yes I totally agree with the above statements, having used them a lot for Diplomatic and Military Communications. 1/2 wave or longer at the lowest intended frequency, these antennas can be useful. Otherwise they start acting more like a dummy load.... .. 73 from, The K0UO " Rhombic Antenna Farm" miles of wire in the Air & On the AIR daily
Thank you for that important piece of advice. I have been on 80 m with a horizontal dipole in 1980s, when there was no space restriction at my parents' home. I could even have gone for 160 m if I had known about activity in that band at the time with low sunspot activity. My current location is limited even for a 20 m dipole with good clearance. Merry Christmas and a Happy New Year in advance! 73 de Jon, VU2JO
Is half wavelength the total length of the antenna wire or the span of the antenna assembly? 73 de VU2JO
