A loop antenna needs to go around the edge of the PCB, free from coupling to other circuits or ground. Not exactly like a coil. You want to figure out which polarization is best for good radiation. I have seen articles in Portable Design and RF Design magazine. Maybe they have archive articles on line? Micrel and Microchip have articles too? I did one at 300 Mhz for a remote transmitter. I tried to keep the drive signal centered and the antenna symmetrical. I depends if your drive is symmetrical or single ended? On you first prototype PCB, try several shorting traces that you can jumper in and out to tweak the signal output as seen on a receiver or spectrum analyzer. Even try soldering copper strips from old PCB maternal to adjust things. Mike Hagen Hagen Engineering -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body