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Delta
A typical delta HF antenna features a triangular shape, with one horizontal arm along the bottom to serve as the base and two vertical arms meeting at the center point to form the top of the triangle. The antenna feed comes through the bottom middle. A delta antenna is a traveling wave antenna, with no standing wave present, so the size of the antenna has no relationship to the transmission signal or the signal being received.
Dipole
In a dipole antenna, a two-wire transmission line is split, so the two wires bend back and create a single straight line. The area where the wire split occurs also contains the antenna feed. A dipole antenna operates on a standing wave, so the ideal length of the antenna should be one-half of the wave signal transmitted or received. Like most resonant antennas, the dipole works best in a narrow band of frequencies.
Inverted V
Perhaps requiring the most space of any HF antenna, an inverted V antenna stems from a single vertical mast, with the V point connected at the top of the mast and the V arms pointing downward. One of the arms connects to the ground through a terminating resistance, leaving the other arm to connect to the antenna feeder. An inverted V antenna must be placed on a hill or on an extremely tall mast to generate space waves, which travel in straight lines to other antennas. Otherwise, if anchored on a flat surface, an inverted V antenna will generate only ground waves that reflect and travel along the Earth's surface.
Log Periodic
A broadband self-tuning antenna, a log periodic antenna contains a series of parallel active elements, the shortest located at one end, with the elements increasing in length to the other end. When operating in low frequencies, the log periodic antenna's longest elements resonate, while the shortest elements serve as directors. In high frequencies, the roles get reversed, with the shortest elements resonating and the longest elements directing.
Rhombic
Another from of traveling wave antenna, a rhombic antenna is shaped like a horizontal rhombus supported on masts, with one mast at each corner of the rhombus frame. A rhombic antenna can be used as an efficient transmitter or as an HF receiving antenna, providing exceptional gain. While a single rhombic antenna can cover the area of a football field, several antennas may be linked to receive long distance shortwave transmissions.