The QuietRadio Aziloop DF-72 Multi-Directional Receive Antenna System is an innovative, low-noise solution for VLF to HF reception. This dual-mode, electronically rotatable HF receive antenna system features a primary frequency range of 20 kHz to 10 MHz, with coverage to 30 MHz at reduced directivity and sensitivity (determined by the size of the user supplied loop antennas). Additionally, the Aziloop system is fed with a single coaxial cable, eliminating the need for bulky antennas and rotators.

Product development was started over 5 years ago by Aziloop creator Dave GW4GTE. The original requirement was for a multi-purpose receive antenna that could be remotely controlled. Nothing suitable existed, and so Aziloop was born.

Unique to the Aziloop DF-72, the Aziloop’s Stepped-Azimuth™ technology offers up to 72 unidirectional headings and 36 bi-directional headings using a pair of user supplied orthogonal loops. This dual-mode capability is enhanced by features such as variable load resistance, signal level control, band filtering, and auxiliary control ports as standard, all of which are managed via a user-friendly Windows app for local, client/server mode, or remote use.

The antenna’s coaxial cable also carries power and control signals to the LCU (Loop Control Unit). This makes antenna upgrades a snap if a coax feeder cable is already in place. There are other advantages too: separate control lines can be a source of unwanted noise pickup, and current loops can exist between feeder and control lines, reducing antenna performance. Cables are fed into the box via compression glands and are clamped using superior quality rising-cage type terminal blocks. The enclosure includes integrated pole mounts allowing installation to be completed quickly and easily with just a couple of cable ties or jubilee clips. When you’re out there fumbling about on a cold day, you’ll be glad of that.

The CIU (Common Interface Unit) circuitry is housed in a small, extruded aluminum box. Normally mounted indoors next to your PC and receiver, it plays a central role in the Aziloop system. The CIU (Common Interface Unit) can be connected directly to a PC’s USB port, or, for a headless remotely controlled server from anywhere an internet connection exists (no PC attached), via the controller’s built-in Ethernet port. The CIU requires a clean 13.8VDC power supply for operation (not included).

The Antenna comprises two user supplied orthogonal loops, identical in size sharing a common vertical axis, and four radials directly underneath, forming a ground plane (or optionally a ground rod can be used instead). The size of the antenna and mounting method is a user decision.

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Who should consider Aziloop?

The Aziloop DF-72 will be of interest to shortwave listeners, radio amateurs, and professional users alike. Applications include general monitoring, co-channel station resolution, basic direction finding, atmospheric and electromagnetic interference reduction, and jamming mitigation. Plus of course just having fun learning about propagation and discovering what your previous antenna was keeping from you.

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Features Summary

Aziloop is unique in offering two antenna modes in one product.

• K9AY Mode, where Aziloop operates as a K9AY terminated loop giving a unidirectional cardioid pattern.

• Loop Mode, producing the classic small loop figure-of-eight bi-directional pattern at low angles, and omni-directional pattern at higher angles.

Rapidly change mode and heading with just a mouse click

Stepped-Azimuth™

In another first for this market, Aziloop DF-72 uses our Stepped-Azimuth™ technology to produce 72 x 5-degree uni-directional headings in K9AY mode or 36 bi-directional headings in Loop mode from a pair of orthogonal loops. The result is a choice of 108 heading/mode combinations.

To be clear, the antenna does not move, rotation is achieved electronically.

Aziloop User Interface for Windows 10 and 11

Intuitive UI (User Interface)

The antenna is controlled by a unique software app. Serious listeners usually employ some sort of computer based SDR receiver. Where better to control your antenna than on-screen next to your receiver display?

Note: Presently, only Microsoft Windows 10 and 11 is supported.

No Control Cables

The antenna’s coaxial cable also carries power and control signals to the LCU (Loop Control Unit). This makes antenna upgrades a snap if a coax feeder cable is already in place. There are other advantages too: separate control lines can be a source of unwanted noise pickup, and current loops can exist between feeder and control lines, reducing antenna performance.

Designed for outdoor use, the LCU is housed in a high-quality, purpose-designed, IP67-rated waterproof enclosure made from ASA (Acrylonitrile styrene acrylate) thermoplastic (as opposed to ABS) for excellent weather and UV resistance, zero corrosion, and minimal condensation. The lid of the enclosure is secured with six stainless steel screws, which clamp it firmly in place via a waterproofing gasket.

Cables are fed into the box via compression glands and are clamped using superior quality rising-cage type terminal blocks. The enclosure includes integrated pole mounts, allowing installation to be completed quickly and easily with just a couple of cable ties or jubilee clips.

Full Control

The LCU has a switchable balanced preamplifier with a gain of nominally 18 dB, optimally placed at the antenna to maximize signal-to-noise ratio and swamp any external noise pickup on the feeder. Ahead of the preamp are three selectable 7-pole filters, two low-pass and one high-pass, to give your receiver (and our preamp) an easier life if needed. The high-pass filter and one low-pass filter overlap to produce a band-pass response as a fourth filter option.

The terminating resistor in K9AY mode is adjustable in 50 Ω increments from 250 Ω to 950 Ω.

The CIU (Common Interface Unit) has a 5-position attenuator: 0 dB, -6 dB, -12 dB, -18 dB, and infinity (which isolates the receiver, terminating it in 50 Ω).

The combination of LCU preamp and CIU attenuator gives around 36 dB of level control, allowing the user to achieve the best balance of signal-to-noise ratio versus dynamic range. The CIU also has two auxiliary I/O lines that can be separately configured as inputs or outputs. These can be operated remotely as well as locally. Uses include additional antenna switching, controlling other equipment, or in a remote scenario, mains-fail indication, intruder alarm, temperature alarm, remote fan control, equipment reboot, etc.

Mute Facility

An auxiliary I/O channel can be set up as a PTT sense line to quickly isolate a connected receiver and protect the LCU from high RF levels. The second channel can be configured as another PTT input or a PTT-out line with a selectable delay. There is also a mute (talk) timer with a visual display within the app.

Omni-Rig 1.2 Support

Provides receiver syncing (keeping Rig A and Rig B in step), PTT muting, Aux I/O control, and auto filter insertion.

The Aziloop DF-72 is a compact, low-profile antenna system designed for Amateur Radio operators and SWL listeners. Enhance your listening experience with the QuietRadio Aziloop DF-72 and discover the difference in quality and performance .

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Be sure to Look under the "Documentation" tab for a complete User Guide and a product review from the May 2024 issue of RADCOM.

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Accessories Included with the Aziloop DF-72

• (1) LCU (Loop Control Unit)

• (2) Pole Mount Adapters for the LCU

• (1) Spare LCU lid screw (m2.5x16mm, stainless steel)

• (4) Cable Ties for attaching the LCU

• (1) CIU (Common Interface Unit)

• (2) SMA to BNC female adapters for CIU

• (4) Adhesive Feet, for CIU

CIU Cable Set

• (1) 3.5mm stereo plug to phono cable (for AUX I/O)

• (1) 2.1mm barrel to an unterminated cable for 13.8 VDC supply.

• (1) USB Type-A to USB Mini Cable