Sirio GPS-27 is a popular 1/2 wave base antenna for 27MHz CB band and 10m shortwave band. Sirio GPS 1/2 is an antenna adapted to work in the CB band, although it has a wide operating range up to and including 29MHz. The CB antenna will withstand up to 750W of power supplied from the transmitter, equipped with a 'dome' element on top - constituting an antistatic system. Installation of the Sirio GPS 1/2 antenna to the mast is presented in the EN instructions, and SWR tuning is done by the final radiator by shortening or lengthening the radiator - however, the distances for different frequencies are already pre-set in the table - connection with channel 19 CB.
This three elements wire Yagi comes along in a great variety of names. On the 11 meter we call it the Skypper on HAM bands we call it the Spider beam or G4ZU. What ever the name is its principle remains the same. It is a full-size 3 elements Yagi with the Director and Reflector bend towards the radiating element. With this comes a small size Yagi with gain 7,3 dB and front to back in the order of 30 dB. It is easy to build. I made mine with fiberglass rods.
For me it is the base antenna, but is a perfect for holiday trips, DX-expeditions. Because it is lightweight, I used a rotor for the TV antenna, Works perfectly!