This is an attractive antenna for the price (about $150 + shipping).

Anyone have experience with them ?

SIRIO SY27-4 Its a 10 meter beam.

There are hundreds of Hams using the 4 element Sirio "CB Beam" on 10 Meters, with great results!

The 4 element Sirio "CB Beam" was designed for the middle of the 11 meter band. (CB Channel 20)

That is 27.205 mhz

You simply take 27.205 and divide it into 28.5, and you will get a number like .97 percent.

Then, take that ratio, and multiply all spacings and element lengths by it, to get the new dimensions for the 10 meter band.