The bullet antenna looks like it could be a winner with guys on 2.4ghz. To boost the power of equipment it is possible to add amps in series with the receiver, transmitter or both. This way you can use an omni antenna and still have good reception. One unit set up for the GPS band is located here
http://www.ien.it/~brida/LNAGPS.htm
If anyone is interested in this type of info let me know. I have been collecting it for some time and have found QHA calculators on the web.