Sirio GPS 27 1/2λ Base 10m Ham Antenna 250W Continuous, 2.15 dBi Gain, Tunable 26.4-29MHz

The Sirio GPS 27 1/2 is a full-size, 1/2λ base station antenna engineered in Italy specifically for 10-metre amateur radio use. With 250W continuous power handling (750W short time CW), a wide tunable frequency range of 26.4–29 MHz, and a gain of 0 dBd (2.15 dBi), it delivers clean, reliable omnidirectional performance across the full 10m band. The 1/2λ design offers a lower radiation angle than a 1/4λ antenna, making it a solid choice for DX-oriented 10m operators who want a no-radials base antenna. Standing at 5950mm (19.52ft) tall and designed for on-mast mounting, it's constructed from aluminium, copper, galvanised steel, and nylon for robust, long-lasting outdoor performance.

Key Features

• 250W continuous power handling (CW)
• 750W short time power handling (CW)
• Gain: 0 dBd / 2.15 dBi
• Wide tunable frequency range: 26.4–29 MHz
• Optimised for 10-metre amateur radio (HAM)
• Omnidirectional radiation pattern
• Linear vertical polarisation
• 1/2λ design — lower radiation angle for improved DX performance
• On-mast mounting
• SO-239 (UHF-Female) connector
• Height: 5950mm / 19.52ft
• Durable materials: aluminium, copper, galvanised steel & nylon
• Made in Italy by Sirio

Technical Specifications

• Type: 1/2λ base antenna
• Radiation: Omnidirectional
• Polarisation: Linear vertical
• Frequency range: 26.4–29 MHz (tunable)
• Systems: 10m amateur (HAM)
• Gain: 0 dBd / 2.15 dBi
• Max power: 750W peak (CW short time) | 250W continuous (CW)
• Connector: SO-239 (UHF-Female)
• Height: 5950mm / 19.52ft
• Mounting: On-mast
• Materials: Aluminium, copper, galvanised steel, nylon
• Country of origin: Italy

Frequently Asked Questions

Does the GPS 27 1/2 require tuning?
Yes. It is tunable across 26.4–29 MHz, allowing you to optimise SWR for your preferred operating frequency within the 10m band. A SWR meter is recommended for initial setup.

What is the advantage of a 1/2λ design over a 1/4λ antenna?
A 1/2λ antenna produces a lower radiation angle compared to a 1/4λ, which concentrates more signal toward the horizon rather than skyward. This makes it better suited for long-distance (DX) contacts on the 10m band.

Does it require radials or a ground plane?
No. The GPS 27 1/2 is a self-contained 1/2λ design that does not require radials or a ground plane, simplifying installation significantly compared to 1/4λ ground-plane antennas.

What is the maximum power it can handle?
It handles 250W continuous (CW) and 750W short time (CW peak), making it suitable for most HF transceivers and moderate linear amplifier use on 10m.

What connector does it use?
It uses an SO-239 (UHF-Female) connector, which accepts a standard PL-259 plug — the most common connector used with HF coaxial feedlines.

How tall is the antenna and will it need planning permission?
The GPS 27 1/2 stands 5950mm (approximately 19.52ft / 5.95m) tall. In the UK, amateur radio antenna installations may fall under permitted development rights, but we recommend checking with your local planning authority if you are unsure.

Is it suitable for permanent outdoor installation?
Yes. It is constructed from aluminium, copper, galvanised steel, and nylon — materials chosen for long-term outdoor durability and corrosion resistance.

Can it be used for CB radio as well as 10m amateur?
The tunable range of 26.4–29 MHz overlaps with the CB band (26.965–27.405 MHz), so it can physically cover CB frequencies.