As I mention in the project I bought one of these:
<a href="http:&#x2F;&#x2F;www.priority1design.com.au&#x2F;shopfront&#x2F;index.php?main_page=product_info&amp;cPath=1&amp;products_id=23" rel="nofollow">http:&#x2F;&#x2F;www.priority1design.com.au&#x2F;shopfront&#x2F;index.php?main_p...</a><p>Turns out the antenna that comes with it is way too small for anything other than manually brushing it against the cats neck knowing exactly where the chip is.<p>However I got some mails from another guy that built a cat feeder thingie. He ended up doing his own, much bigger antenna so that the cats head fit through it (he made a structure in cardboard wrapping the coil around that).<p>Anyway, he had some contact with the company, and they recommend using the RS232 version instead of the USB one for such applications... They had some better spec in some way.<p>EDIT:
I looked up the mail, and to summarize he used 0.6mm enamled copper wire and a 120mm computer fan (minus the fan in the middle, that he wrapped the coil around. The reader then outputs the MOF value so you can know what frequency you&#x27;re getting.<p>I&#x27;ve bought some copper wire myself and I&#x27;m planning to make a better antenna myself, but haven&#x27;t yet.