Automatic Control Unit
What is a magnetic loop antenna?
"Magnetic" because they take the magnetic component of a electromagnetic field, in contrast to the normal standard antennas (e.g. Dipole, Yagi, Vertical-antenna), which are in resonance only on the electric component.
Magnetic antennas can be created very compactly. Ideal in areas of limitated space or where mobility is required e.g. boats. No radials are required. The radiation is always the same, irrespective of the distance to the ground.
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...
The antennas provide a small bandwidth on their resonance frequency. They have the advantage of less harmonics, and the effect of an additional preselector, focusing on just the required signal, ignoring non-required signals and intermodulation.
Automatic Control Unit
The loop is made of aluminium. Even the smallest antenna has a 50mm ( 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 14mm (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).
Automatic Control Unit
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
The automatic control unit has a tuning circuit installed and is operated with a small keyboard: just enter the desired frequency, wait a few seconds for automatic tuning of the antenna and go. No trying, no lost notes on settings, no checking with the SWR meter. The current frequency and SWR is shown on the LC display. Maximum power load is 250W with the automatic control unit! A 230V power supply is included in the control unit.
Loop Antenna Presentation and Instruction Manual| 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 load | 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. incl. automatic control unit |
11250 1095.10 (1063.20) EUR Buy now | 11251 1246.30 (1210.00) EUR Buy now | |
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.
An affordable solution to make your Baby loop rotateable. Uses the Yaesu G-250 rotator (not included). COnsists of a support bearing and the rotator platform, reduces stress on the rotator. The rotator is fitted on the lower platform, the antenna goes on top. Including brackets and hardware for 50mm masts. Made of aluminum, tube is stainless steel.
Midsize antenna, ideal for 80m up to 20m with continuous covering, manufactured on a stable aluminium reed with a diameter of 75mm
(ca. 3 inch). Loop diameter is 2m (ca. 78 inch), can be mounted without radials, like all loop-antennas.
The manual controller of older models is still available as a spare part.
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