T2FD Antennas: Construction, Projects, and Resources
Find resources for building and understanding T2FD (Tilted Terminated Folded Dipole) antennas for various ham radio applications.
The T2FD, or Tilted Terminated Folded Dipole, is a broadband HF antenna design known for its wide frequency coverage and relatively low SWR across multiple bands. Hams often choose the T2FD for its versatility, especially when space is limited or when operating conditions require quick band changes without retuning. While not always as efficient as a resonant monoband antenna, its ability to cover a broad spectrum makes it a practical choice for general amateur radio activity and shortwave listening.
Operators can find various construction articles and design considerations for building their own T2FD antennas, including detailed instructions for specific band coverage like 10-20 meters. Resources also include modeling insights to understand its performance characteristics and even calculators, such as the T2FD Calculator, to determine proper dimensions for a desired frequency range. Many hams use the T2FD for general QSOs, DX chasing, and even as an attic antenna for SWL.
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"Some have called the T2FD a ""squashed rhombic"" antenna. It does bear some design similarities to the non resonant rhombic, but theoretically it is admittedly inferior. However, the T2FD performs well in a modest amount of space." -
T2FD A practical construction article, which first appeared in the Electronic DX Press, contains a number of useful photos and detailed instruction to build this antenna by VK3BVW -
Using the T2FD antenna for shortwave listening by AB1KW -
Building the Balanced Termination Folded Dipole -
T2FD is a 600-900 ohms folded dipole, terminated with resistor. Feed impedance is coupled with 50/600 ohms voltage balun. It is a wide band antenna with rather low SWR over the full designed frequency range: antenna tuner is seldom needed. -
An Excel sheet calculator for the T2FD wire antenna. The sheet has been proved to work either on LibreOffice and Apple Numbers. Just input the resonating frequency to get the proper size and dimensions. -
Wikipedia page dedicated to the T2FD antenna -
This project describes the construction of a W3HH (T2FD) antenna for HF bands (3-30 MHz). While less efficient than a tuned dipole, it offers broad frequency coverage with a maximum SWR of 3.4 and reduces QRM (noise) significantly. On the 80-meter band, it shows slightly weaker signals than a dipole but with improved signal-to-noise ratio. The design includes non-inductive resistors, a 13:1 balun, and a "frog ladder" transmission line. Though not a high-performance antenna, it is compact and versatile, making it ideal for wide-band HF communication. Article in French