There are 2 types of cantenas: 1) Picks up signals 2) Sends signals.
Simply not true, the gain of an antenna is about the same wether sending or receiving.
As an analogy, I can use a telescope to see faint light far away, or I can shine a faint light through a telescope to project the light much further, same thing works both ways
During normal wi-fi operation your antenna needs to do both sending and receiving equally well, not just because of normal network operations but because of the ack packets required by 802.11 protocols
Imagine web browsing as a simple example - you send http requests and get back web pages, normal two-way traffic. But even when you receive the pages you have to send acknowledgement packets back to the access point - if an ack is not received for a particular packet, it will be resent.
Due to global warming, eskimos now have more than 20 words for water John O'FarrellProfessional geek, consultant and trainer.
MCT, MCSA, MMI, MBMSS, CWNA, COS (I like to have lettuce after my name)
My personal blog - Getting IT right