Maria Maluca three-band antenna
A Maria Maluca three-band antenna is a directional antenna for receiving or transmitting electromagnetic waves in the short-wave range .
description
Maria Maluca is the sloppy Portuguese term for "crazy girl". The Maria Maluca three-band antenna is mainly used by financially weak radio amateurs in Latin America . The directional antenna has been designed for the amateur radio bands 10, 15 and 20 m. It represents a replica-proof three-band antenna that can be produced with the simplest means as a compromise solution for DX radio traffic .
10 m amateur radio band
The antenna acts as a 2-element directional antenna for the 10 m band. In this case, the parasitic element acts as a director that is a little too long and is spaced λ / 6 from the feed dipole. The fed dipole is a dipole extended by approx. 50% for the 10 m band.
15 m amateur radio band
The antenna acts as a full-length half-wave dipole with less director effectiveness in the 15 m band. In this case, the director is at a distance of λ / 8 from the feeding dipole. The lower effectiveness results from the fact that the director is dimensioned for the 21 MHz band. A director effect of the parasitic element can still be determined.
20 m amateur radio band
In the 20 m band, the antenna acts like a shortened dipole. In this volume, the director has very little effect. In the 20 m band, the antenna probably acts like a full-length half-wave dipole.
Feeding the three-band antenna
The Maria Maluca three-band antenna is fed via a 300 Ω feed line of a certain length. The length of the feed line can be 11.70 m, 18.50 m or 23.55 m. Optimal operating results can only be achieved with these feed lines.
literature
- Karl Rothammel Y21BK: Antennenbuch , 9th edition, Franckh'sche Verlagshandlung, W. Keller & Co., Stuttgart 1988, ISBN 3-440-05853-0