Sirio SD 27 Dipole 27MHz antenna

The Sirio SD 27 Dipole is a high-quality dipole antenna for users who expect maximum performance from their base station. This professional Sirio antenna is designed for reliable communication within the frequency range of 26.5 to 30 MHz, making it excellent for use as a 27MC antenna and for the 10-meter amateur band.

Thanks to its robust construction, high power capacity, and excellent tuneability, this base antenna offers stable performance under various conditions. Whether you are an amateur radio operator, making DX connections, or want to build a powerful 27MC base station, the Sirio SD 27 Dipole delivers the reliability and quality for which Sirio is globally renowned.

Professional base antenna for optimal range

The Sirio SD 27 Dipole is constructed as a 1/2 λ dipole antenna and offers an omnidirectional radiation pattern. This provides uniform coverage around the antenna, ideal for local and longer-range connections.

With a gain of 2.15 dBi and a wide bandwidth of more than 3.5 MHz at an SWR of maximum 2, this antenna is easy to tune within the full frequency range of 26.5 to 30 MHz.

The waterproof coupling sleeve protects the connections from moisture and weather influences, making the antenna suitable for long-term outdoor installations.

Developed for high power

This Sirio antenna is designed for users who operate with higher transmission powers. The SD 27 Dipole effortlessly handles a maximum of 1000 Watts continuous (CW) and even up to 3000 Watts for short periods.

Thanks to the use of high-quality materials such as aluminum alloy 6063 T-832, galvanized steel, and Zamak, this base antenna offers an excellent combination of strength, durability, and performance.

With a total length of over 5.5 meters, the antenna delivers optimal efficiency within the 27 MHz frequency range.

Why choose the Sirio SD 27 Dipole?

• Professional dipole antenna for base stations
  
• Suitable as a 27MC antenna and for the 10-meter amateur band
  
• Tunable from 26.5 to 30 MHz
  
• Waterproof coupling sleeve for long-term outdoor use
  
• High power up to 1000 Watts continuous and 3000 Watts peak
  
• Robust construction from high-quality materials
  
• Omnidirectional radiation pattern for optimal coverage

The Sirio SD 27 Dipole is the ideal choice for anyone looking for a reliable base antenna with excellent performance on the 27MC band and the 10-meter amateur band. Thanks to the combination of quality, power, and durability, you are assured of years of interference-free use.

Available parts

• Sirio SA088/Q mounting set for SD/SY series antennas
• Sirio SA089/Q mounting sleeves for the SD/SY series antennas

Order your Sirio SD 27 Dipole today at Deltron.nl and bring professional communication performance to your base station.

Installation of the Sirio SD Dipole

The Sirio SD Dipole, such as the popular SD-27 and SD-FM models, can be mounted in various ways. The performance of the antenna depends on the chosen setup and polarization.

1. Vertical mounting: In a vertical installation, the two antenna elements point straight up and down. In this configuration, the antenna operates omnidirectionally, meaning signals are transmitted and received equally in all directions. This setup is ideal for general local and mobile traffic where communication around the antenna is desired.
2. Horizontal mounting: In a horizontal installation, the antenna elements are perpendicular to the mast and point left and right. In this configuration, the antenna becomes more directional, allowing signals from certain directions to be better received and transmitted. This can offer advantages for specific connections or fixed communication links.

Important considerations during installation

• Mast mounting: The antenna comes with a sturdy mounting bracket suitable for masts with a diameter of approximately 35 to 52 mm.
• Gamma Match adjustment: The Gamma Match (the antenna's tuning unit) must be correctly mounted for optimal performance. In vertical mounting, the Gamma Match is located at the top of the dipole. In horizontal mounting, it should be directed upwards or horizontally, depending on the instructions in the manual.
• Antenna tuning: For optimal performance, the antenna must be tuned to the desired frequency band, such as the 11-meter CB band, 10-meter amateur band, or other applicable frequencies. This is done by adjusting the length of the radiators according to the supplied tuning instructions.
• Connecting the coaxial cable: Run the coaxial cable (e.g., RG-58 or RG-213 with PL-259 connector) as straight as possible downwards from the feed point. Also, ensure a good waterproof seal of the connectors to prevent moisture problems and performance loss.

Correct installation and SWR tuning ensure that the Sirio SD Dipole performs optimally and enables reliable communication for years.

Mounting instructions for the antenna elements

These instructions can also be found in English on the last two product photos. You can also download the manual on this page, which can be found under the 'manual' tab below the product photos.

• 1.0 Extend the telescopic elements by pulling out the Ø12 tube and assemble the connecting sleeve. Secure the first element with the supplied Phillips screw. Then mount the second connecting sleeve, slide the top Ø8 tube including the PVC end cap together, and secure the end with the supplied Phillips screw.
• 1.1 Placement of the elements on the boom - See the image in the instructions.
• 1.2 Mounting of the elements on the boom. Slide the tuning element of the Gamma Match over one of the dipole radiator elements. Then place the elements in the metal holder and secure them with the supplied screws and Allen key.
• 2.0 Mounting the Gamma Match. Extend the last tube of the Gamma Match to a length of L1 = 485 mm. Attach the flattened Ø12 end to the connector using the supplied nut and washer, but do not fully tighten yet. Slide the tuning element towards the boom and extend the Ø8 end of the Gamma Match to a length of L = 890 mm. Then secure the tuning element with the supplied screw and Allen key. Double-check that dimensions L and L1 are correct. Then definitively tighten the nut on the flattened part of the Gamma Match and place the PVC protective cap.
• 3.0 Mounting the bracket on the antenna boom. See the image in the instructions.

Please note

Do not overtighten the nuts you use to secure it. Excessive tightening torque can cause damage to the antenna.

• 3.1 Mounting on the support tube. See the image in the instructions.
• 4.0 Connecting the coaxial cable. See the image in the instructions.