Magnetic Loop antennas by Ciro Mazzoni

Special features of the Baby and Midi Loop Antenna

The loop is made of aluminium. Even the smallest antenna has a 50 mm ( 2 inch) diameter of the tubing. Because of the large surface area there is less loss of gain. Both ends are welded on the socket, no screw connections so no contact resistance.

The tuning capacitor on our loops is not a simple variable capacitor but a big variable plate capacitor of aluminium with an air-dielectric. Both plates are also welded directly to the loop and indestructible on high power! The distance between the plates is 14 mm (ca. 1/2 inch) on the smallest antenna.

A weather resistant actuator opens or closes the loop and thus tunes the plate capacitor (SWR tuning).

The capacitance can be varied by a motor and can be adjusted to the best SWR via a control unit in your shack. In spite of their compact size, the antennas are resonant in a wide frequency-range - do you know of any antenna which has a diameter of just one meter (ca. 38 inch) but a frequency range of 40m ... 10m without gap?? Take this one...

Tuning of the antennas is done with either a manual or an automatic control unit. The control units have a 230V power supply integrated.

Automatic control unit

Loop Controller

The tuning of the antenna is done with an automated control unit. This controller is supplied with a 230V power supply. Operation is handled by a small numeric USB keyboard: Enter the desired frequency, wait a moment, ready. The antenna has tuned automatically and is ready to transmit after a short while. No difficult tuning process, no note taking, no complicated search for lowest SWR. The display shows frequency and SWR for immediate check, some LEDs signal the current state of the controller. The max. power load with the automatic controller is 250W! An english manual is included in shipment.

The new version of the controller, which is shipped since spring 2016 contains a RS-232 interface. This interface will allow direct frequency control by certain radios in the future (requires software update). The frequency information is directly transferred from the radio (Icom [1], Kenwood, Yaesu, Elecraft) to the controller, the antenna tunes automatically to the current frequency. Further an Ethernet interface will be available later as a hardware option. A serial RS-485 interface is provided for future extensions.

The new version of the automatic controller is available separately as well and can be used with older models of the manufacturer.

[1]: Icom transceivers require a level converter like the CT-17 or similar.

Download: Loop-Manual (PDF, EN, 5MB)
Technical Data
Model BABY MIDI
Frequency Range 6,6-29.8 3,5-14,5 MHz
Diameter 1,0 2,0 m
Impedance 50 50 Ω
Max. Power 250 250 Watt
Front/Side ratio 25-35 25-35 dB
Inductivity 3 µH
Q 1100 (7 MHz)
Weight 12 20 Kg
Tube diameter 50x2 75 mm
Surface of antenna 0,25 qm
Max. Mast Diameter 76 76 mm
Control unit with LC display Optional Optional
Order No.
11250 Baby Loop incl. autom. control unit V2 1365.00 € Buy now
11251 Midi Loop incl. autom. control unit V2 1540.00 € Buy now
11253 Automatic Control Unit V2 649.00 € Buy now New
11250.X01 Mounting platform for antenna as supplied 99.00 € Buy now New
Info freight charges

BABY Loop: 6.6 to 29.8 MHz

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The smallest and most popular selling loop-antenna. Diameter is only 1m (ca. 38 inch). For this antenna space is not a problem: on the balcony, on the roof. The gapless frequency-range is 6,9 up to 29,7 MHz. It comes ready to use with mast clamp. Please order the control unit separately.

Order No.
11250 Baby-Loop 1365.00 € Buy now
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MIDI Loop: 3.5 to 14.5 MHz

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Midsize antenna, ideal for 80m up to 20m with continuous covering, manufactured on a stable aluminium reed with a diameter of 75 mm (ca. 3 inch). Loop diameter is 2m (ca. 78 inch), can be mounted without radials, like all loop-antennas.

Order No.
11251 Midi-Loop 1540.00 € Buy now
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Controlwire for Loop antennas

The Magnetic Loop antennas with manual tuning require four wire for control, the antennas with the automatic controller require two wires. The smallest cable we offer is a five or a six wire cable. With this cable you could 2x2 wires in parallel for manual tuning, or 2x3 in parallel for automatic tuning. Due to the enlarged diameter very long cable runs are possible.

Order No.
40010.5 Control cable, 5 x 0,75mm2, per meter 1.10 € Buy now
40010.6 Control cable, 6 x 0,75mm2, per meter 1.30 € Buy now
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