Bricks, Masonry, Asphalt and Concrete - screw bracket on brick chimney wall

I am installing a outdoor antenna for my new HDTV. In order not to put the mast on top of the roof, I plan to use a longer mast to extend the mount point of the mast into the middle of the wall - 5 feet above ground on the brick wall.

There are total three mount points, two tripes on upper and lower side of chimney which will secure the upper part of the mast. One wall mount bracket on the brick wall as described above will secure the lower part of the mast.

My question: how can I screw the bracket on the brick wall? Screw on the brick or the mortar? I don't think I can find the stud behind the brick wall. Thank you very much for any advice.

not bricks as a general rule,,, then you can use lead plugs into which you'll drive screws/lags,,, i probably wouldn't use conc screws in this instance because of their shear strength.

There are total three mount points, two tripes on upper and lower side of chimney which will secure the upper part of the mast. One wall mount bracket on the brick wall as described above will secure the lower part of the mast.

BTW, can't tell from your post if you are attaching part of this to a masonry chimney above its highest attachment to the structure, but per IRC R1003.8, "Chimneys shall not support loads other than their own weight unless they are designed and constructed to support the additional load." and I do occasionally see masonry chimneys at home inspections that have been damaged by the attachment of antennas.