The Sirio Gain Master 5/8 is a premium, centre-fed 5/8 wave base station antenna engineered in Italy for CB 27MHz and 10-metre amateur radio use. Covering the full 25.5–30 MHz range with no tuning required, it delivers 1–2 dB more gain than conventional 5/8λ antennas and handles up to 500W continuous (CW) — making it one of the most capable base antennas available at this price point. Updated in 2024 with a new plastic reinforcement sleeve for added durability. Standing at an impressive 7360mm (24.15ft) tall and designed for on-mast mounting, it's built from anodised aluminium, copper, stainless steel, fibreglass, and UV-stabilised thermoplastic to withstand years of outdoor use. Key Features 500W continuous power handling (CW) Full 25.5–30 MHz coverage — no tuning required 1–2 dB gain advantage over conventional 5/8λ antennas Compatible with CB 27MHz & 10-metre amateur radio Omnidirectional radiation pattern Linear vertical polarisation 0.625λ centre feed design for superior performance On-mast mounting SO-239 (UHF-Female) connector Height: 7360mm / 24.15ft 2024 update: new plastic reinforcement sleeve Premium materials: anodised aluminium, copper, stainless steel, fibreglass & UV-stabilised thermoplastic Made in Italy by Sirio Technical Specifications Type: 0.625λ centre feed base antenna Radiation: Omnidirectional Polarisation: Linear vertical Frequency range: 25.5–30 MHz (no tuning required) Systems: CB 27MHz / 10m amateur (HAM) Gain: 1–2 dB above conventional 5/8λ Max power: 500W continuous (CW) Connector: SO-239 (UHF-Female) Height: 7360mm / 24.15ft Mounting: On-mast Materials: Anodised aluminium, copper, stainless steel, fibreglass, UV-stabilised thermoplastic Country of origin: Italy Frequently Asked Questions Does the Sirio Gain Master 5/8 require tuning?No. It covers the full 25.5–30 MHz range with no tuning required, making it ready to use straight out of the box across all CB 27MHz and 10m amateur channels. Can it be used for both CB and 10m amateur radio?Yes. The antenna covers both CB 27MHz and the 10-metre amateur band (28–29.7 MHz) within its 25.5–30 MHz range, making it a versatile choice for licensed amateurs and CB operators alike. What is the gain advantage over a standard 5/8 wave antenna?The Gain Master delivers 1–2 dB more gain than a conventional 5/8λ antenna, thanks to its 0.625λ centre-fed design which optimises the radiation pattern for improved range and signal strength. What mast diameter is required for mounting?The Gain Master is designed for on-mast mounting. Sirio recommends a mast diameter compatible with their standard clamps — typically 30–60mm. Check the included hardware or Sirio’s documentation for the exact clamp specification. What coax 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 antenna stands 7360mm (approximately 24.15ft / 7.36m) tall. In the UK, amateur radio antenna installations may be subject to permitted development rights. We recommend checking with your local planning authority if you are unsure. Is it suitable for permanent outdoor installation?Yes. It is constructed from anodised aluminium, copper, stainless steel, fibreglass, and UV-stabilised thermoplastic — all materials chosen for long-term outdoor durability and corrosion resistance. What is the maximum power it can handle?The Gain Master is rated at 500W continuous (CW), making it suitable for high-power HF transceivers and linear amplifiers used on CB and 10m.
