Momobeam Tetra18‑DF 40/20/15/10M Dual‑Feed Yagi Antennas represent a versatile and high‑performance quad‑band antenna solution engineered for operators who demand exceptional results. These antennas deliver efficient, optimized performance while maintaining a compact structure, making them ideal for contesting, DXing, and multi‑station operation.

On 40 meters, the Tetra18‑DF antennas use a classic Reflector/Driver configuration, with element lengths compacted through end‑loading. This design approach, originally adopted by W6NL, preserves the on‑air performance and gain characteristics of a full‑size 40‑meter Yagi while significantly reducing the physical span of the elements. The result is a mechanically manageable 40‑meter system that still performs like a full‑sized antenna.

Across 20, 15, and 10 meters, these antennas employ full‑size elements arranged in proven high‑gain configurations: four elements on 20 meters, five elements on 15 meters, and seven elements on 10 meters. This design provides excellent forward gain, clean patterns, and wide bandwidth without the compromises of traps, loading coils, or mechanical switching systems. Because no traps, motors, relays, or other moving parts are used, the antennas achieve exceptional long‑term reliability and mechanical simplicity. All components are built from durable, high‑quality aluminum to ensure performance and longevity in demanding environments.

The dual‑feed system is a defining feature of the Tetra18‑DF antennas. It enables contest stations to operate these antennas as true multi‑monoband systems. One transceiver/amplifier can operate on 20/15/10 meters, while a second station transmits on 40 meters simultaneously—an arrangement made possible by the fully isolated feed architecture. This configuration maximizes multi‑operator efficiency, with the only added requirement being the use of external band‑pass filters (BPFs) to protect equipment between stations.

Each Tetra18‑DF antenna is supplied with a dedicated Assembly Tool, spare hardware, and two aluminum tube sections to ensure smooth installation and long‑term maintainability. Additionally, two high‑quality 3kW RF choke baluns are included as standard equipment—a significant advantage, as many manufacturers treat these essential components as optional add‑ons.

Assembly is straightforward thanks to the use of a square boom, clearly labeled aluminum elements, and individually packaged and labeled hardware. These design choices make the construction process intuitive and efficient, even for first‑time installers. The system requires two coaxial feedlines—one dedicated to the 40‑meter feed point and the other feeding 20/15/10 meters —and a heavy‑duty rotator to accommodate the overall mechanical load.

Momobeam Tetra18‑DF Dual‑Feed Yagi Antennas offer outstanding quad‑band performance, unmatched reliability, and advanced operating flexibility. They are engineered to satisfy contest‑grade requirements while maintaining ease of installation and long‑term mechanical stability, making them a standout choice for serious HF stations seeking the highest levels of performance across the 40/20/15/10‑meter bands.

Tetra1-DF Features and Specifications:

• RF Choke Balun: (2) 3kW included

• Bandwidth@ S.W.R. ≤ 1.5:1:

40M - 200kHz

20M – 350kHz

15M – 450kHz

10M – 800kHz

• Longest element: 55.77ft. (1700cm)

• Power Handling: 10kW

• Wind Area: 26.91 sq. ft. (2.5m²)

• Wind Load: (80 MPH): (1525N) 1124.78 ft. lbs.

• Wind Survival*: 100 Mph (160 Km/h)

• Tower Leg/Mast Diameter: 2.0-2.36in. (50/60mm)

• Tower Lift Side: 4.92ft. (150cm) Weight: 289.60lbs. (130kg)

• Feedline Connector: (2) 50-Ohm UHF SO-239 female

• Tubes and Plates: Aluminum alloy 6061T6

• Hardware: stainless steel

• Insulating Clamps: polypropylene, UV resistant