Full-wave loop antennas can be large at lower frequencies, but they are quieter than dipoles and have more gain broadside to the plane of the loop. A circular loop is ideal, but squares, triangles, and other shapes can work well; just make the area enclosed by the loop as big as you can.

You can use a full-wave loop on frequencies higher than design frequency as well (for example, using a 7 MHz loop on 21 MHz), but the pattern will be different.

To use the calculator, enter the desired operating frequency in megahertz.

The calculated length is approximate. In practice it's best to make the antenna a little longer than the calculated value and then trim it to get the best SWR value.

The feedpoint impedance at the design frequency is about 100 ohms, so full wave loops are often fed with an impedance-matching section made from a piece of 75-ohm coxial cable one quarter wavelength long (shortened to compensate for the velocity factor of the cable).

The formulas for calculating the approximate length of a full-wave loop antenna are:

**Full-wave loop in feet = 1005 / frequency in MHz****Full-wave in meters = 306 / frequency in MHz**

The formulas for calculating the length of an impedance matching section are:

**Quarter-wave matching section length in feet = 246 * cable's velocity factor / frequency in MHz****Quarter-wave matching section length in meters = 75 * cable's velocity factor / frequency in MHz**

The velocity factor for polyethylene coax is usually 0.66. For foam-dielectric cable, it's usually 0.8.

The antenna can be connected by other means, of course, including parallel-conductor lines, which work best when using the antenna on multiple bands.

Home |

Check out the recommended reading list |

Calculators |

Small Transmitting Loop Antennas | ||||

Full-Wave Loop Antennas | ||||

Quarter-Wave Vertical Antennas | ||||

Coil-Shortened Vertical Antennas | ||||

Dipole Antenna Length | ||||

Coil-Shortened Dipole Antenna | ||||

Coil Inductance | ||||

Toroid Coil Winding | ||||

Wire Gauge & Diameter | ||||

Capacitance (Capacitor Design) | ||||

Capacitive Reactance (Xc) | ||||

Inductive Reactance (XL) | ||||

Body Mass Index (BMI) Calculator | ||||

CO2 & the Planted Aqaurium |

Recommended (free) Software |

Computers |

Create a Database Table from a Spreadsheet | ||||

Export a Database Table to a Spreadsheet | ||||

RCA Universal Remote: Learning |

VBar Flybarless Controller |

Accessing an Extra Channel on your mini VBar | ||||

Setting up the Governor on your mini VBar | ||||

Calculate Headspeed with your mini VBar Governor | ||||

Copyright © 1999-2024 66pacific.com. All rights reserved.