Loop Antennas
last updated 28 November 2023.
Loop antennas come in various sizes and shapes, with very different characteristics. As we did with Loop Antenna Theory, we will them into the following types:
- small receiving loops, less than about 0.1 wavelengths, where the current is approximately constant around the loop. These have a broadside null and maximum radiation off the edges.
- small transmitting loops, where efficiency is more important.
- full wave loops, (generally between 2/3 and 3/2 wavelengths) which have maximum radiation broadside to the loop. This is probably the most common loop for ham radio use.
- large loops, 2 wavelengths or more, which have maximum radiation off the sides of the loop, and may have a broadside null. These may simply be a full wave loop on one band used on other higher bands, which can make a very effective multiband antenna.
We will also look at some of the intermediate cases, which can be quite useful, and some antennas that look like loops but technically aren’t:
- intermediate loops, around 1/4 wavelength or so
- half wavelength loops, an early directional antenna
- Loop antenna beams and arrays (quads, delta loops, Sterba Curtains, Bruce arrays, double rectangles, etc.)
- bisquare antenna, 2 wavelengths around but open at the top.
Popular Loop Antenna Projects
- Construction of wire loop antennas
- Figure-8 Bow Tie multiband horizontal loop
- 80m Horizontal Loop Antenna for Field Day
- Portable 200 ohm loop antenna
- Wire quad antennas
- 5-element 20m Portable Delta Loop beam
- simple 2m 2-element quad
- Feeding large loops
- Double loops
- hand-held DF loop for 40m through 15m
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