What is a Delta Loop Antenna?

What is a Delta Loop Antenna?

Delta loop antenna is a full wave length antenna in the shape of the Greek alphabet Delta (Δ). The antenna forms a Δ shape with limbs like an equilateral triangle. Though it can be made with base at the top, bottom or sides, practically it will be easy to have the base at the top as shown in the picture below. It will need a 4:1 balun at the feed point for impedance matching. Otherwise the SWR (Standing Wave Ratio) will be high.

As with the half-wave dipole antenna, a delta loop antenna for 7 MHz will also function well with the odd multiple frequency of 21 MHz. On 14 MHz the antenna impedance is high and SWR will be high. For the centre of 7 MHz amateur radio band, with frequency of 7.1 MHz, the length of the delta loop will be 43.14 m. Delta loop antenna is fairly easy to construct if you can put up two strong poles. Recommended height is above 18.3 m for a 40 m antenna, which comes down to 4.6 m for a 15 m delta loop.