Looking at the specs they are the same just one has a patch antenna and the other has the connector. But from most peoples use of the current setup you would not need an external antenna unless you are trying to go though a thick concrete wall or have your computer over 200 feet from your show. Also with using an outside antenna you may interfere with someone else equipment if some one in your neighborhood also has a Lynx wireless system.
Ray
one rule of radio use only use the power you need to get the job done, more is not better.