The Stiro Loop by Ciro Mazzoni has been designed to provide an effective antenna for users with limited space. One of the goals was to build an antenna that was not immediately recognizable as an antenna. The Stealth Loop covers a frequency range of 6.6 to 29.8 MHz (45 to 10 m), maximum power is 125 W CW. Compared to an ideally mounted fullsize dipole, the antenna has a signal gain of about 4 dB less at 40m, and about 0.3dB less than 10m. The usable band that can be used without retuning is about 5 kHz on 40 m and 25 kHz on 10 m. Usually a SWR of 1.3: 1 or better is obtained.
The construction of the Stealth loop follows the same principle as the well-known "Baby" and "Midi" loop antennas of Ciro Mazzoni: one side of the loop is fixed, the other side moves with a stepper motor around a joint. Both halves end with interlocking condenser plates on the upper side, forming the magnetic circuit tuning capacitor. Both sides of the loop are connected with a very wide and flexible steel band that is connected to the frame with multiple screws for better conductivity and lower resistance. The circumference of the Stealth loop is about 282 cm, only slightly lower than that of the Baby cycle. The cycle size is 137 x 50 x 26 cm, the weight is approx. 10 kg. The cycle frame is professionally welded by 60 x 20 mm wide aluminum tubes.
The directional loop pattern is slightly directional at very low elevation angles and based on frequency. At the largest elevation angles the model becomes almost round and without null values. Overall, the model also influences the position and conductivity of the ground beneath the antenna. The circuit should only be used outdoors, not inside a building. The minimum space for any solid structures should be about 2 m at the sides and above the antenna. Solid structures are walls, roofs, railings, etc. The positioning of the Stealth is very flexible: you can place it on the floor or on the roof of a car, on a balcony or a garden desk, everything can be as long as the minimum you get a side / top game of 2m.
A two-wire control cable in addition to the coaxial cable is required for operation. 5 m cable with connector are included. If a longer cable is required, you can extend the supplied length or mount the connector on another cable. Included in the shipment is the automatic tuning unit (ATU 2.0) incl. Accessories. This controller offers the possibility to automatically follow the radiofrequency through the CAT control. In semiautomatic mode it is possible to enter the frequency on a keyboard. The tuning process takes between 4 and 10 seconds, depending on the frequency change.
- It has Stealth Loop
- Frequency range 6.6 - 29.8 MHz
- Max. Transmit power 125 W continuous (FT-8, CW, RTTY)
- Unknowing construction
- Low weight, also suitable for portable operations
- Automatic tuning unit included
- CAT control for Elad, Elecraft, Flex, Icom, Kenwood, Yaesu
- Delivery volume
- Stealth Loop
- ATU 2.0 Conroller
- 10 keyboards (USB)
- 24V power supply
- Motor cable with connector, 5m
- Printed manual (Italian, English)