If I had to come up with a list of the top 5 technical resources ever, the CC-Antenna-DK kit from TI (formerly Chipcon) would definitely place pretty high up there.  Antenna design is a time consuming, repetitive task requiring an excellent attention to detail and understanding of the materials you’re working with, more than a few calculations, and a dash of trial and error.  $49.00 for more than a dozen pre-rolled, easy to test, easy (and legal!) to steal antennas is seriously one of the best deals I’m yet to come across.  Heck, they even throw in short, load and open boards if you’re in a pinch and need a cheap way to calibrate your VNA!  The frequencies are a bit biased towards Europe with a lot of 868MHz boards (no surprise since Chipcon was Norwegian), but if you’re looking for an excellent primer in antenna design, including complicated ones like mixing 868MHz and 2.4GHz in the same antenna, you’ll definately benefit from reading some details on this excellent board.  See Design Note DN031: CC-Antenna-DK and Antenna Measurements Summary.  And if you’re interested in RF at all, seriously … buy one now before someone at TI wises up and starts charging the $495.00 this board is really worth!