OctaLoop Mini a shielded active Loop antenna 1 MHz – 30 MHz (40M-10M Optimized)

All our products are handmade, and fulfilment times may vary depending on order volume. Please allow 2–3 weeks for your order to be completed and shipped.

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Included:

• OctaLoop Mini Antenna (60cm wide)
• Stainless Steel (RVS316) Mounting Bracket
• Bias-T 13.8V F-Type to SMA
• Short SMA to BNC Cable
• 10M INTSAT-170-ELITE 75Ω coax cable with 2 F-Type Connectors

Optional:

• RVS Ground Peg (including F connector bulkhead) and RX RF Line Isolator

Product Description: The OctaLoop Mini is a high-performance HF active shielded H-field magnetic loop antenna, engineered for exceptional low-noise signal reception. Designed for both urban and remote environments, it significantly reduces EMI and improves signal clarity.

Compact, highly sensitive, and optimized for HF monitoring, the OctaLoop is an ideal solution for shortwave listening (SWL), amateur radio DXing, and SDR applications. Its shielded magnetic loop design and build in common mode rejection, ensures superior rejection of local interference, allowing for clearer, more stable reception across the HF band.

With an impressive IP3 of +41 dBm due to a push-pull design, the OctaLoop delivers outstanding dynamic range and signal fidelity. Covering 500 kHz – 50 MHz, but optimized for HF 7MHz – 30 MHz, it is a versatile and reliable choice for serious radio enthusiasts and professional monitoring applications.

Placement Recommendations: For optimal performance, install the OctaLoop at a location well away from buildings, power lines, and other sources of electromagnetic interference (EMI). The antenna operates most effectively at a height of 1.2 to 5 metres, providing a balance between noise reduction and signal reception.

Read more: Height vs. Performance: Optimizing the OctaLoop Active Magnetic Loop Antenna

If the feedline to the loop is longer than 10 metres, you can install a CMR choke midway along the feedline to minimise noise.

Grounding: For improved performance, grounding the braid of the coaxial cable feedline to a proper earth ground is highly recommended. Avoid grounding the coaxial cable to the mast itself—grounding should be performed at the base of the mast instead.

Test It Yourself!
Experience the OctaLoop’s performance in real-time by tuning into one of our SDR receivers: https://rf.guru/sdr

Do you need a rotor ? Understanding the Null of a Shielded Active H-Field Loop Antenna

Why an Octaloop is Superior to a Square or Circular Loop Antenna

Deep Nulls and Their Use in Noise Rejection

One of the most significant advantages of the OctaLoop is its sharp nulling capability. Unlike omnidirectional antennas, a magnetic loop exhibits a well-defined directional pattern.

• The deep nulls are present at the sides of the loop (broadside to the loop plane), making it highly effective at rejecting noise sources coming from specific directions.
• This deep nulling effect is particularly beneficial in rejecting local interference from nearby power lines, electric fences, and household appliances, where an operator can rotate the antenna to null out unwanted signals.
• The depth of the null is frequency-dependent, being most pronounced in the MW and lower HF bands.

Polarization and Take-Off Angle

Unlike vertical or horizontal wire antennas, the OctaLoop primarily receives magnetic field (H-field) components rather than the electrical field (E-field). This has several advantages:

• Lower susceptibility to local noise, as most electrical interference is in the E-field domain.
• Polarization: The received signal is predominantly magnetically coupled, which means it is less affected by multipath interference.
• Take-off angle: The antenna pattern is typically low-angle at lower frequencies, making it ideal for groundwave and DX reception. However, its reception pattern can be influenced by its mounting height and surrounding environment.

Handling Different Signal Types

The OctaLoop can effectively receive:

• AM broadcast signals (MW band) with exceptional clarity due to its noise rejection capabilities.
• CW (Morse Code) and SSB transmissions, where signal-to-noise ratio is critical.
• Weak DX signals, especially in low bands such as 80m, and 40m.
• Utility signals, including NAVTEX and time signals.
• Propagation beacons, which are useful for assessing band conditions.

Ideal Use Cases and Placement

For best results, the OctaLoop should be placed away from large metal structures and rotated to optimize nulling against interference sources. It is well-suited for both indoor and outdoor use, with options for mast mounting or temporary setups for field operations.

Frequency Range and Performance Expectations

The OctaLoop is well-suited for reception across the low-frequency (LF), medium-wave (MW), and lower high-frequency (HF) bands, offering different levels of efficiency depending on the frequency range:

Performance Considerations by Band

Upper HF (7 MHz – 30 MHz)

• Peak performance range for this loop size.
• Highly directional with deep nulls, making it effective for reducing local QRM.
• Ideal for SWL, utility signal reception, and maritime/aviation communications.
• Suitable for shortwave broadcasting, utility stations, and high-frequency amateur bands (40m, 30m, 20, 17m, 15m, 12m and 10m).

Mid HF (2 MHz – 7 MHz)

• Efficiency gradually decreases as frequency decreases.
• Covers 160m, 80m providing medium reception and good noise suppression.
• Deep nulling is less effective, but still useful for minimizing man-made noise.
• Can still receive signals, but may not provide the same level of selectivity and noise rejection as at higher frequencies.

Technical Data:

• Frequency Range: 500 kHz – 50 MHz
• Impedance: 75 Ohm
• Power Supply: 13.8V, approx. 180mA
• Polarization: Horizontal
• Connection: F-Connector
• Antenna Size: 1.2m diameter, 3.65m circumference
• Weight: Approx. 1.2 kg
• Working Temperature: -20°C to +50°C
• Pole Mount: 30-68 mm

Scope of Delivery:

• OctaLoop Mini Antenna with enclosure and mounting bracket
• Bias-T Power Injector
• 10m INTSAT-170-ELITE 75Ω coaxial cable with F-Type connectors
• SMA-to-BNC adapter cable

Upgrade your HF reception with the OctaLoop Mini – engineered for precision, built for performance.