Ciro Mazzoni Baby Loop

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Ciro Mazzoni BABY Automatic Magnetic Loop Antenna provides transmit and receive continuous coverage across 6.6 - 29.8 MHz which includes all of the 40 - 10 meter HF amateur radio bands. It is made of aircraft grade aluminum. The tuning capacitor is an air-variable type made of thick aluminum plates. Each set of capacitor plates is welded directly to opposite portions of the top of the loop.

The weather-resistant actuator motor changes the loop diameter, causing it to expand or contract and thus adjusts the integral capacitor for tuning. Resonance is adjusted by a control unit in the shack. Although resonant bandwidth is very small (as with all compact loops) tuning is very smooth and easily accomplished when you change bands or change frequency within the band.

Ciromazzonibabyloop200.jpg

The included ATU 2.0 loop controller allows RS-232 direct-frequency control by certain radios. In rigs with CAT or CI-V output, antenna tuning will automatically track the VFO and band changes. The frequency information is directly transferred from the radio to the controller, and then the antenna tunes automatically to the current frequency.

Manual tuning is also possible using the ATU 2.0 controller’s small numeric USB keyboard. The user will enter the desired frequency, wait a moment, and the loop is tuned. The ATU 2.0 display shows frequency and SWR immediately and LEDs signal the status of the controller. The controller uses a very low-power DDS oscillator to tune the loop so it will tune through an amplifier. It is not necessary to transmit in order to tune.

BABY Loop technical data

  • Frequency Range: 6.6 - 29.8 MHz
  • SWR: 1.3:1 typical
  • Impedance: 50 ohms nominal (gamma matched)
  • Maximum Input (PEP and CW): 450 W up to 21 MHz; 1 kW from 22 to 29.8 MHz
  • Front/back ratio 6dB
  • Front/Side ratio: 25 dB
  • Antenna Tube diameter: 1.968 in. (50mm)
  • Wind loading: 0.25 square meters (2.70 sq. ft.)
  • Wind Survival: 100 mph
  • Control cable pair: 20 AWG (or 18-2) up to 65 ft.; 16 AWG (or 14-2) up to 100 ft.; 12 AWG (12-2) over 100 ft.
  • Weight: 26.4 lbs. (12 Kg)
  • Capacitor Depth: 8.5 in. (0.215m)
  • Loop Width: Approx. 40 in. (1.0m)
  • Loop Height: 50.5 in. (1.3m) from top of capacitor to loop hinge base
  • Overall Height: Approx. total 60 in. (1.5m) from top of capacitor to bottom of included mast bracket
  • Mast Bracket Height: 11.5 in. (0.3m)
  • Maximum Mast Diameter: 2.362 in. (60mm)
  • Minimum Mast Diameter: 1.967 in. (50mm)
  • Assembly hardware: Stainless steel

Maximum Input (PEP and CW): 450 W up to 21 MHz; 1 kW from 22 to 29.8 MHz. The ATU 2.0 unit handles 200W max. from transceiver and operates on 24 Vdc at 2A (2.1mm input) from a 120/220 Vac International plug power supply.

The Ciro Mazzoni baby loop mk2 latest version as of 2024.

Review

Having received the antenna and completed initial assembly it should be stated that it seems very well built. This is no flimsy MFJ plastic easily broken ham toy. This antenna looks and feels like a well built commercial or military grade piece of equipment.

To perform testing the antenna will be mounted on a pole 5' off the ground and connected to an Icom IC-7600 transceiver.

Test results will be shared here...

Initial finding is that the antenna seems to perform strongly on 20 meter and secondly on 40 meter, with the lowest SWR on 40 and overall best signal reports on 20. Initial testing on the 10 meter band were inconclusive or perhaps somewhat disappointing.

On the 20 meter band signal reports from distant stations stated a strong and clear signal. More testing will be necessary under different band conditions, however, at this point the results suggest the antenna radiates well but may not be ideal for reception of very weak stations. Yet, that may not be true because although signal reception levels are lower compared to the dipole, the noise is dramatically reduced. This antenna is "quiet" in that local area man made noise is almost completely eliminated. This makes it easier to "hear" and discern voices on weak signals that would otherwise be lost in the noise.

There is some directivity in that it does not behave like a beam but does have a distinctly present null. Rotation of the antenna is not needed as frequently as would be with a beam. Setting a general direction suffices unless you want to make a significant compass direction change. I would suggest that beyond 45 degree increments, fine rotation is not necessary at all.

Criticisms of the documentation are warranted. You will find yourself conducting some trial and error on things that could have been eliminated by proper documentation. Some of these shortcomings will be documented here as time permits.

Assembly and Installation Tips

Since the instruction manual covers assembly and installation the process will not be repeated here as the manual is available free online from DXEngineering (recommended) and from the manufacturer web site (same except larger document in many languages.) What will be covered here are some tips and suggestions that will be helpful where the documentation fails to provide adequate information as well as some tips based on experience with the antenna system.

Issue #1: Documentation at the time of this writing does not describe proper wiring with regards to polarity for the motor controller wiring from the antenna to the station control unit. Wiring backwards will result in an error on the controller unit.

Issue #2: Initial movement and bolt/screw torque. You may have to loosen bolts at movement points or where it is hinged. You may also have to physically by hand slightly nudge the

Resources

There are currently no good youtube reviews or assembly videos at this time. Everything discovered via search was horrible, vertical video, poorly done, and not useful at all.

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