Antenne a Loop Magnetico per Ciro Mazzoni

Stealth Loop Nuovo

Stealth Loop

The Stealth Loop by Ciro Mazzoni was designed to provide an effective antenna to users with limited space. One goal was to build an antenna which is not instantly recognizable as an antenna. The Stealth Loop covers a frequency range from 6.6 to 29.8 MHz (45 to 10m), the maximum power is 125 W CW. Compared to an ideally mounted fullsize dipole the antenna has about 4 dB less signal gain on 40m, and about 0.3dB less on 10m. The useable bandwith which can be used without retuning is about 5 kHz on 40m, and 25 kHz on 10m. Usually an SWR of 1.3:1 or better is achieved.

The construction of the Stealth loop follows the same principle as the well known 'Baby' and 'Midi' loop antennas by Ciro Mazzoni: One side of the loop is fixed, the other side moves by a stepper motor around a joint. Both halves end in interlocking capacitor plates on the upper side, this forms the tuning capacitor of the magnetic loop. Both sides of the loop areconnected with a very wide, flexible steel band which is connected to the frame with multiple screws for best conductivity and lowest resistance. The circumference of the Stealth loop is approximately 282 cm, only slightly less than that of the Baby loop. The dimension of the loop are 137 x 50 x 26 cm, the weight is approx. 10 kg. The frame of the loop is professionally welded from 60 x 20mm wide aluminium tubes.

Stealth Loop Pattern Stealth Loop Pattern

The directional pattern of the loop is slightly directional at very low elevation angles, and depending on the frequency. At hugher elevation angles the pattern becomes nearly round and without nulls. Overall the pattern is also influence by the position and ground conductivity below the antenna. The loop should be operated only outdoors, not inside a building. The minimum clearance to any solid structures should be around 2m to the sides and above the antenna. Solid structures are walls, roofs, railings etc. The placement of the Stealth is very flexible: you can put it on the floor as well as on the roof of a car, on a balcony or garden desk, everything goes as long as the minimum sideways/top clearance of 2m is achieved.

For operatin you need a two wire control cable besides the coaxial cable. 5m cable with connector are included. In case you need a longer cable you can extend the supplied length or mount the connector to another cable. Included in shipment is the automatic tuning unit (ATU 2.0) incl. accessories. This controller offers the possibility to automatically follow the radio frequency by CAT control. In half-automatic mode the frequency can be entered on a keyboard. The tuning process takes between 4 and 10 seconds, depending on the change of frequency.

Stealth Loop SWR Diagram Stealth Loop SWR Diagram
  • Features Stealth Loop
  • Frequency range 6.6 – 29.8 MHz
  • Max. transmit power 125W continous (FT-8, CW, RTTY)
  • Inconspicious construction
  • Low weight, even suitable for portable operations
  • Automatic Tune Unit included
  • CAT control for Elad, Elecraft, Flex, Icom, Kenwood, Yaesu
  • Volume di consegna
  • Stealth Loop
  • ATU 2.0 Conroller
  • 10 keypad (USB)
  • 24V Power Supply
  • Motor cable with connector, 5m
  • Printed Manual (italian, english)
Ordine No.
11252 Stealth Loop 40-10m 1340.00 € Aggiungi al carello Nuovo In magazzino, spedizione in 1 o 2 giorni.
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Stealth Loop Detail Stealth Loop Detail

Particolarità del Baby e Midi Loop Antenna

Sono costruite in alluminio. Anche la piu' piccola ha l'elemonto di 50 mm di diametro( 2 inch). A causa della 'ampia superficie' hanno meno perdita di guadagno. Entrambi i tratti terminali sono saldati al connettore evitando cosi' resistenze di contatto .

Il condensatore di sintonia non e' un semplice variabile ma un ' grande' condensatore con lamelle di alluminio in dielettrico in aria. Entrambe le armature sono saldate direttamente alla loop e resistenti alle alte potenze! La distanza tra le armature , nell'antenna piu' piccola, e' 14 mm (ca. 1/2 inch) .

Un attuatore impermeabile apre e chiude le armature permettendone la sintonia (SWR tuning).

La Capacita' puo' essere variata da un motore e si puo' tarare per aver il miglior SWR con una unita' di controllo. Contrariamente alle loro limitate dimensioni , esse sono risonanti in un ampio spettro di banda - es ...conoscete una qualsivoglia antenna che ha un diametro di 1 metro ma un range di frequenza dai 40 m. 10 m. senza interruzione di continuita' ?? ..Ecco...questa ..per esempio..

Unità di controllo automatica

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 allows direct frequency control by certain radios. The frequency information is directly transferred from the radio (Icom, Elecraft, Kenwood, Yaesu) to the controller, the antenna tunes automatically to the current frequency. Further an Ethernet interface will be available later as a hardware option.

The new version of the automatic controller is available separately as well and can be used with older models of the manufacturer. To interface an Icom transceiver, an optional level converter is required.

Download: Loop-Manual 04/2018 (PDF, IT/EN, 56 MB)
Dati tecnici
Gamma di frequenze 6,6-29.8 3,5-14,5 MHz
Diametro 1,0 2,0 m
Impedenza 50 50 Ω
Potenza mass. 250 250 Watt
Front/Side rapporto 25-35 25-35 dB
Induttivita' 3 µH
Q 1100 (7 MHz)
Peso 12 20 Kg
Diametro del 'tubo' 50x2 75 mm
Superficie dell 'antenna 0,25 qm
Diametro Asta mass. 76 76 mm
Unita' di controllo con display Option Option
Ordine No.
11250 Baby Loop con unità di controllo automatico 1399.00 € Aggiungi al carello In magazzino, spedizione in 1 o 2 giorni.
11251 Midi Loop con unità di controllo automatico 1580.00 € Aggiungi al carello In magazzino, spedizione in 1 o 2 giorni.
11253 Unità di controllo automatico V2 649.00 € Aggiungi al carello Nuovo In magazzino, spedizione in 1 o 2 giorni.
11250.X01 Mounting platform for antenna as supplied 99.00 € Aggiungi al carello Nuovo Non in magazzino, verrà ordinato solo su richiesta, tempi di consegna c. 40 giorni.
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BABY Loop: 6.6 to 29.8 MHz

11250_f.jpg (13387 Byte)

La piu' piccola e popolare loop-antenna. Diametro di solo 1m (ca. 38 inch). Per questa antenna non vi sono problemi di spazio: sul balcone..sul tetto. Il da 6,9 fino a 29,7 MHz.Arriva 'pronta' per l'uso con il mast clamp.

Ordine No.
11250 Baby-Loop 1399.00 € Aggiungi al carello In magazzino, spedizione in 1 o 2 giorni.
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swr_baby.gif (2994 Byte)

MIDI: 3.5 to 14.5 MHz

11251_f.jpg (6564 Byte)

Antenna di medie dimensioni, ideale per la gamma 80m fino ai 20m con copertura continua, di resistente tubo di alluminio di diametro 75 mm (ca. 3 inch).Il diametro del Loop e' 2m (ca. 78 inch), si puo' montare senza radiali,come tutte le antenne Loop.

Ordine No.
11251 Midi-Loop 1580.00 € Aggiungi al carello In magazzino, spedizione in 1 o 2 giorni.
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swr_midi.gif (2528 Byte)

MIDI Loop with JW4PUA on Spitsbergen, 1000km north of the polar circle

Cavo di controllo per antenne loop

Le antenne Loop Magnetico con accordo manuale richiedono quattro fili per il controllo, le antenne con il controllo automatico ne richiedono due. Il cavo più piccolo che offriamo è a cinque o sei conduttori. Con questo cavo puoi accoppiare i cavi 2x2 per l'uso in manuale, o 2x3 per l'uso in automatico. Grazie al grande diametro è possibile usare cavi molto lunghi.

Ordine No.
40010.6 Control cable, 6 x 0,75mm2, per meter, 8mm Ø 1.40 € Aggiungi al carello In magazzino, spedizione in 1 o 2 giorni.
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